Document and Entity Information (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Feb. 13, 2013	Jun. 30, 2012
Document and Entity Information [Abstract]
Entity Registrant Name	Kaiser Aluminum Corp
Entity Central Index Key	0000811596
Document Type	10-K
Document Period End Date	Dec. 31, 2012
Amendment Flag	false
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 974.3
Entity Common Stock, Shares Outstanding		19,313,235

Consolidated Balance Sheet (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 273.4	$ 49.8
Short-term investments	85.0	0
Receivables:
Trade, less allowance for doubtful receivables of $0.8 at December 31, 2012 and $0.9 at December 31, 2011, respectively	123.8	98.9
Other	3.4	1.2
Inventories	186.0	205.7
Prepaid expenses and other current assets	70.1	78.9
Total current assets	741.7	434.5
Property, plant, and equipment — net	384.3	367.8
Net asset in respect of VEBA	365.9	144.7
Deferred tax assets — net (including deferred tax liability relating to the VEBAs of $136.9 at December 31, 2012 and $47.6 at December 31, 2011 - see Note 7)	102.0	226.9
Intangible assets — net	35.4	37.2
Goodwill	37.2	37.2
Other assets	86.0	72.3
Total	1,752.5	1,320.6
Current liabilities:
Accounts payable	62.5	62.2
Accrued salaries, wages, and related expenses	39.3	30.9
Other accrued liabilities	51.9	41.0
Payable to affiliate	7.9	14.4
Long-term debt-current portion	0	1.3
Total current liabilities	161.6	149.8
Net liability in respect of VEBA	5.3	20.6
Long-term liabilities	134.5	126.0
Long-term debt	380.3	151.4
Total liabilities	681.7	447.8
Commitments and contingencies — Note 11
Stockholders’ equity:
Preferred stock, 5,000,000 shares authorized at both December 31, 2012 and December 31, 2011; no shares were issued and outstanding at December 31, 2012 and December 31, 2011	0	0
Common stock, par value $0.01, 90,000,000 shares authorized at both December 31, 2012 and at December 31, 2011; 21,037,841 shares issued and 19,313,235 shares outstanding at December 31, 2012; 20,977,791 shares issued and 19,253,185 shares outstanding at December 31, 2011	0.2	0.2
Additional paid in capital	1,017.7	998.4
Retained earnings	151.2	84.4
Common stock owned by Union VEBA subject to transfer restrictions, at reorganization value, none at December 31, 2012 and 2,202,495 shares at December 31, 2011	0	(52.9)
Treasury stock, at cost, 1,724,606 shares at December 31, 2012 and December 31, 2011	(72.3)	(72.3)
Accumulated other comprehensive loss	(26.0)	(85.0)
Total stockholders’ equity	1,070.8	872.8
Total	$ 1,752.5	$ 1,320.6

Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Receivables:
Allowance for doubtful receivables	$ 0.8	$ 0.9
Deferred tax liability relating to VEBAs	$ 136.9	$ 47.6
Stockholders' equity:
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	90,000,000	90,000,000
Common Stock, Shares, Issued	21,037,841	20,977,791
Common Stock, Shares, Outstanding	19,313,235	19,253,185
Common stock owned by Union VEBA, shares	0	2,202,495
Treasury stock, shares	1,724,606	1,724,606

Statements of Consolidated Income (USD $)
In Millions, except Share data in Thousands, unless otherwise specified

12 Months Ended

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Net sales

$ 1,360.1

$ 1,301.3

$ 1,079.1

Cost of products sold:

Cost of products sold, excluding depreciation and amortization and other items

1,116.2

1,129.0

946.1

Unrealized (gains) losses on derivative instruments

(15.2)

29.9

0.7

Restructuring benefits

(0.3)

Depreciation and amortization

26.5

25.2

19.8

Selling, administrative, research and development, and general

62.2

62.7

67.7

Other operating charges (benefits), net

4.5

(0.2)

4.0

Total costs and expenses

1,194.2

1,246.3

1,038.0

Operating income

165.9

55.0

41.1

Other (expense) income:

Interest expense

(29.1)

(18.0)

(11.8)

Other income (expense), net

2.8

4.3

(4.2)

Income before income taxes

139.6

41.3

25.1

Income tax provision

(53.8)

(16.2)

(13.1)

Net income

$ 85.8

$ 25.1

$ 12.0

Earnings per common share, Basic:

Net income per share

$ 4.49

$ 1.32

$ 0.61

Earnings per common share, Diluted:

Net income per share1

$ 4.45

^[1],[2]

$ 1.32

^[1],[2]

$ 0.61

^[1],[2]

Weighted-average number of common shares outstanding (in thousands):

Basic

19,115

^[3]

18,979

^[3]

19,377

^[3]

Diluted1

19,278

^[2]

18,979

^[2]

19,377

^[2]

[1]	Diluted weighted-average number of common shares outstanding and diluted earnings per share for 2012 is based on the treasury method. Diluted weighted-average number of common shares outstanding and diluted earnings per share for 2011 and 2010 are based on the two-class method (see Note 1 and Note 14).
[2]	The diluted weighted-average number of common shares outstanding and diluted earnings per share for 2012 were calculated using the treasury method. The diluted weighted-average number of common shares outstanding and diluted earnings per share for 2011 and 2010 were calculated using the two-class method (see Note 1).
[3]	The basic weighted-average number of common shares outstanding during the period excludes unvested share-based payment awards.

Statements of Consolidated Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 9.1	$ 29.2	$ 21.0	$ 26.5	$ 6.1	$ 4.1	$ 4.1	$ 10.8	$ 85.8	$ 25.1	$ 12.0
Defined benefit pension plan and VEBAs
Net actuarial gain (loss) arising during the period									87.8	(110.6)	25.5
Reclassification adjustments relating to VEBAs:
Amortization of net actuarial loss									3.1	0.6	0.7
Amortization of prior service cost									4.2	4.2	4.2
Other comprehensive income (loss) relating to defined benefit pension plan and VEBAs									95.1	(105.8)	30.4
Unrealized gain (loss) on available for sale securities									0.6	(0.1)	0.1
Foreign currency translation adjustment									(0.2)	0.2	(0.5)
Other comprehensive income (loss), before tax									95.5	(105.7)	30.0
Income tax (expense) benefit related to items of other comprehensive income (loss)									(36.5)	40.4	(11.5)
Other comprehensive income (loss), net of tax									59.0	(65.3)	18.5
Comprehensive income (loss)									$ 144.8	$ (40.2)	$ 30.5

Statement of Consolidated Stockholders' Equity (USD $)
In Millions, except Share data, unless otherwise specified

Total

Common Stock

Additional Paid in Capital

Retained Earnings

Common Stock Owned by Union VEBA

Treasury Stock

Accumulated Other Comprehensive Income (Loss)

Beginning balance at Dec. 31, 2009

$ 870.3

$ 0.2

$ 967.8

$ 85.0

$ (116.4)

$ (28.1)

$ (38.2)

Beginning balance, shares at Dec. 31, 2009

20,276,571

Stockholders' Equity [Roll Forward]

Net income

12.0

Other comprehensive income, net of tax

18.5

Release of restriction on Union VEBA shares, net of tax of $19.6, $25.0, and $41.3 for 2010, 2011, and 2012, respectively)

32.5

0.7

31.8

^[1]

Issuance of warrants

14.3

Issuance of non-vested shares to employees

97,931

Issuance of common shares to directors, shares

4,612

Issuance of common shares to directors

0.2

Issuance of common shares to employees upon vesting of restricted stock units and performance shares

4,934

Cancellation of employee non-vested shares

(5,968)

Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares

(11,729)

Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares

(0.4)

Repurchase of common stock, shares

1,151,900

Repurchase of common stock

44.2

Cash dividends on common stock ($0.96, $0.96 and $1.00 per share for 2010, 2011, and 2012, respectively)

(19.0)

Amortization of unearned equity compensation

4.5

Ending balance at Dec. 31, 2010

888.7

0.2

987.1

78.0

(84.6)

(72.3)

(19.7)

Ending balance, shares at Dec. 31, 2010

19,214,451

Stockholders' Equity [Roll Forward]

Net income

25.1

Other comprehensive income, net of tax

(65.3)

Release of restriction on Union VEBA shares, net of tax of $19.6, $25.0, and $41.3 for 2010, 2011, and 2012, respectively)

40.5

8.8

31.7

^[1]

Issuance of non-vested shares to employees

83,066

Issuance of common shares to directors, shares

3,750

Issuance of common shares to directors

0.2

Issuance of common shares to employees upon vesting of restricted stock units and performance shares

17,444

Cancellation of employee non-vested shares

(2,889)

Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares

(62,637)

Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares

(3.1)

Cash dividends on common stock ($0.96, $0.96 and $1.00 per share for 2010, 2011, and 2012, respectively)

(18.9)

Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest

0.2

Amortization of unearned equity compensation

5.2

Reclassification relating to dividends on unvested equity awards

0.2

Ending balance at Dec. 31, 2011

872.8

0.2

998.4

84.4

(52.9)

(72.3)

(85.0)

Ending balance, shares at Dec. 31, 2011

19,253,185

Stockholders' Equity [Roll Forward]

Net income

85.8

Other comprehensive income, net of tax

59.0

Release of restriction on Union VEBA shares, net of tax of $19.6, $25.0, and $41.3 for 2010, 2011, and 2012, respectively)

67.3

14.4

52.9

^[1]

Issuance of non-vested shares to employees

92,949

Issuance of common shares to directors, shares

3,930

Issuance of common shares to directors

0.2

Issuance of common shares to employees upon vesting of restricted stock units and performance shares

11,327

Cancellation of employee non-vested shares

(2,355)

Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares

45,801

Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares

2.2

Cash dividends on common stock ($0.96, $0.96 and $1.00 per share for 2010, 2011, and 2012, respectively)

(19.6)

Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest

1.3

Amortization of unearned equity compensation

5.6

Reclassification relating to dividends on unvested equity awards

0.6

Ending balance at Dec. 31, 2012

$ 1,070.8

$ 0.2

$ 1,017.7

$ 151.2

$ 0

$ (72.3)

$ (26.0)

Ending balance, shares at Dec. 31, 2012

19,313,235

[1]	At $24.02 per share reorganization value.

Statement of Consolidated Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 85.8	$ 25.1	$ 12.0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property, plant and equipment	24.7	23.0	19.5
Amortization of definite-lived intangible assets	1.8	2.2	0.3
Amortization of debt discount and debt issuance costs	9.8	8.6	4.5
Deferred income taxes	52.0	17.6	13.3
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	(1.3)	(0.2)	0
Non-cash equity compensation	5.8	5.4	4.7
Net non-cash LIFO (benefit) charges	(4.9)	(7.1)	16.5
Non-cash unrealized (gains) losses on derivative instruments	(16.0)	25.9	5.5
Amortization of option premiums paid (received), net	0.3	(1.2)	1.8
Non-cash impairment charges	4.4	0	4.6
(Gain) losses on disposition of property, plant and equipment	(0.1)	0.2	0.1
Non-cash net periodic benefit (income) costs	(11.5)	(5.7)	5.1
Long-term assets and liabilities, net	1.2	0.4	(0.7)
Changes in operating assets and liabilities, net of effect of acquisition:
Trade and other receivables	(27.1)	(8.3)	(1.2)
Receivable from affiliate	0	0	(0.2)
Inventories (excluding LIFO adjustments)	24.6	(24.5)	(56.3)
Prepaid expenses and other current assets	1.4	(2.9)	(0.9)
Accounts payable	(1.3)	10.9	4.2
Accrued liabilities	10.4	(1.5)	0.4
Payable to affiliate	(6.5)	(2.7)	8.1
Long-term assets and liabilities, net	(1.1)	(2.4)	24.6
Net cash provided by operating activities	152.4	62.8	66.3
Cash flows from investing activities:
Capital expenditures	(44.1)	(32.5)	(38.9)
Purchase of available for sale securities	(85.0)	(0.3)	(4.4)
Proceeds from disposal of property, plant and equipment	0.3	0.7	4.8
Cash payment for acquisition of manufacturing facility and related assets (net of $4.9 of cash received in connection with the acquisition in 2011)	0	(83.2)	(9.0)
Change in restricted cash	6.9	(1.0)	1.1
Net cash used in investing activities	(121.9)	(116.3)	(46.4)
Cash flows from financing activities:
Proceeds from issuance of Senior Notes	225.0	0	0
Proceeds from issuance of Convertible Notes	0	0	175.0
Purchase of call option in connection with issuance of cash convertible senior notes	0	0	(31.4)
Proceeds from issuance of warrants	0	0	14.3
Repayment of capital lease	(0.1)	(0.1)	0
Repayment of promissory notes	(4.7)	(8.3)	(0.7)
Cash paid for financing costs	(6.6)	(2.1)	(8.6)
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	1.3	0.2	0
Repurchase of common stock to cover employees' tax withholdings upon vesting of non-vested shares	2.2	3.1	0
Repurchase of common stock	0	0	44.2
Cash dividend paid to stockholders	(19.6)	(18.9)	(19.0)
Net cash provided by (used in) financing activities	193.1	(32.3)	85.4
Net increase (decrease) in cash and cash equivalents during the period	223.6	(85.8)	105.3
Cash and cash equivalents at beginning of period	49.8	135.6	30.3
Cash and cash equivalents at end of period	$ 273.4	$ 49.8	$ 135.6

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2012

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Organization and Nature of Operations. Kaiser Aluminum Corporation (together with its subsidiaries, unless the context otherwise requires, the “Company”) specializes in the production of semi-fabricated specialty aluminum products, such as aluminum sheet and plate and extruded and drawn products, primarily used in aerospace/high strength, general engineering, automotive, and other industrial end market applications. The Company has one operating segment, Fabricated Products. See Note 15 for additional information regarding the Company's reportable segment and its other business units.

Principles of Consolidation and Basis of Presentation. The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries, and are prepared in accordance with United States generally accepted accounting principles (“GAAP”) and the rules and regulations of the Securities and Exchange Commission (the “SEC”). Intercompany balances and transactions are eliminated. The consolidated financial statements include the results of manufacturing facilities acquired by the Company from the effective date of each acquisition.

The Company has suspended the use of the equity method of accounting with respect to its 49% non-controlling ownership interest in Anglesey Aluminium Limited ("Anglesey"), which owns and operates a secondary aluminum remelt and casting facility in Holyhead, Wales. As a result, the Company did not record equity in income from Anglesey for any of the periods presented herein. The carrying amount of the Company's investment in Anglesey was zero at both December 31, 2012 and December 31, 2011. The Company does not anticipate resuming the use of the equity method of accounting with respect to its investment in Anglesey during the next 12 months.

Use of Estimates in the Preparation of Financial Statements. The preparation of financial statements in accordance with GAAP requires the use of estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities known to exist as of the date the financial statements are published, and the reported amounts of revenues and expenses during the reporting period. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of the Company’s consolidated financial statements; accordingly, it is possible that the actual results could differ from these estimates and assumptions, which could have a material effect on the reported amounts of the Company’s consolidated financial position and results of operations.

Recognition of Sales. Sales are generally recognized on a gross basis when title, ownership and risk of loss pass to the buyer and collectability is reasonably assured. A provision for estimated sales returns from, and allowances to, customers is made in the same period as the related revenues are recognized, based on historical experience or the specific identification of an event necessitating a reserve.

From time to time, in the ordinary course of business, the Company may enter into agreements with customers in which the Company, in return for a fee, agrees to reserve certain amounts of its existing production capacity for the customer, defer an existing customer purchase commitment into future periods and reserve certain amounts of its expected production capacity in those periods for the customer, or cancel or reduce existing commitments under existing contracts. These agreements may have terms or impact periods exceeding one year.

Certain of the capacity reservation and commitment deferral agreements provide for periodic, such as quarterly or annual, billing for the duration of the contract. For capacity reservation agreements, the Company recognizes revenue ratably over the period of the capacity reservation. Accordingly, the Company may recognize revenue prior to billing reservation fees. Unbilled receivables are included within Trade receivables on the Company's Consolidated Balance Sheets (see Note 2). For commitment deferral agreements, the Company recognizes revenue upon the earlier occurrence of the related sale of product or the end of the commitment period. In connection with other agreements, the Company may collect funds from customers in advance of the periods for which (i) the production capacity is reserved, (ii) commitments are deferred, (iii) commitments are reduced or (iv) performance is completed, in which event the recognition of revenue is deferred until the fee is earned. Any unearned fees are included within Other accrued liabilities or Long-term liabilities, as appropriate, on the Company's Consolidated Balance Sheets (see Note 2).

Stock-Based Compensation. Stock-based compensation in the form of service-based awards is provided to executive officers, certain employees and directors, and is accounted for at fair value. The Company measures the cost of services received in exchange for an award of equity instruments based on the grant-date fair value of the award and the number of awards expected to ultimately vest. The cost of an award is recognized as an expense over the requisite service period of the award on a straight-line basis. The Company has elected to amortize compensation expense for equity awards with graded vesting using the straight-line method (see Note 10).

The Company also grants performance-based awards to executive officers and other key employees. These awards are subject to performance requirements pertaining to the Company's economic value added (“EVA”) performance, measured over specified three-year performance periods. The EVA is a measure of the excess of the Company's adjusted pre-tax operating income for a particular year over a pre-determined percentage of the adjusted net assets of the immediately preceding year, as defined in the Company's annual long-term incentive (“LTI”) programs. The number of performance shares, if any, that will ultimately vest and result in the issuance of common shares depends on the average annual EVA achieved for the specified three-year performance periods. The fair value of performance-based awards is measured based on the most probable outcome of the performance condition, which is estimated quarterly using the Company's forecast and actual results. The Company expenses the fair value, after assuming an estimated forfeiture rate, over the specified three-year performance periods on a ratable basis (see Note 10).

Shipping and Handling Costs. Shipping and handling costs are recorded as a component of Cost of products sold excluding depreciation, amortization and other items.

Advertising Costs. Advertising costs, which are included in Selling, administrative, research and development, and general, are expensed as incurred. Advertising costs for 2012, 2011 and 2010 were $0.4, $0.4, and $0.3, respectively.

Research and Development Costs. Research and development costs, which are included in Selling, research and development, and general, are expensed as incurred. Research and development costs for 2012, 2011 and 2010 were $6.4, $6.1, and $4.9, respectively.

Major Maintenance Activities. All of the major maintenance costs are accounted for using the direct expensing method.

Cash and Cash Equivalents. The Company considers only those short-term, highly liquid investments with original maturities of 90 days or less when purchased to be cash equivalents. The Company’s cash equivalents consist primarily of funds in commercial paper, savings accounts, demand notes, money market funds and other highly liquid investments, which are classified within Level 1 of the fair value hierarchy with the exception of commercial paper, which is classified within Level 2 of the fair value hierarchy.

Restricted Cash. The Company is required to keep certain amounts on deposit relating to workers’ compensation and other agreements. The Company accounts for such deposits as restricted cash (see Note 2).

Trade Receivables and Allowance for Doubtful Accounts. Trade receivables primarily consist of amounts billed to customers for products sold. Accounts receivable are generally due within 30 to 60 days. For the majority of its receivables, the Company establishes an allowance for doubtful accounts based upon collection experience and other factors. On certain other receivables where the Company is aware of a specific customer’s inability or reluctance to pay, an allowance for doubtful accounts is established against amounts due, to reduce the net receivable balance to the amount the Company reasonably expects to collect. However, if circumstances change, the Company’s estimate of the recoverability of accounts receivable could be different. Circumstances that could affect the Company’s estimates include, but are not limited to, customer credit issues and general economic conditions. Accounts are written off once deemed to be uncollectible. Any subsequent cash collections relating to accounts that have been previously written off are typically recorded as a reduction to total bad debt expense in the period of payment.

Inventories. Inventories are stated at the lower of cost or market value. Finished products, work-in-process and raw material inventories are stated on the last-in, first-out (“LIFO”) basis. The Company recorded net non-cash LIFO inventory (benefits) charges of approximately $(4.9), $(7.1) and $16.5 during 2012, 2011 and 2010, respectively. These amounts are primarily a result of changes in metal prices and changes in inventory volumes. The excesses of current cost over the stated LIFO value of inventory at December 31, 2012 and December 31, 2011 were $24.5 and $29.4, respectively. Inventory volume decreased during the year ended December 31, 2012, the effect from the liquidation of the 2011 LIFO layer was $22.3. Other inventories, principally operating supplies and repair and maintenance parts, are stated at average cost. Inventory costs consist of material, labor and manufacturing overhead, including depreciation. Abnormal costs, such as idle facility expenses, freight, handling costs and spoilage, are accounted for as current period charges. All of the Company's inventories at December 31, 2012 and December 31, 2011 were included in the Fabricated Products segment (see Note 2 for the components of inventories).

Property, Plant, and Equipment - Net. Property, plant and equipment is recorded at cost (see Note 2). Construction in progress is included within Property, plant, and equipment - net in the Consolidated Balance Sheets. Interest related to the construction of qualifying assets is capitalized as part of the construction costs. The aggregate amount of interest capitalized is limited to the interest expense incurred in the period. The amount of interest expense capitalized as construction in progress was $1.7, $1.3 and $2.8 during 2012, 2011 and 2010, respectively.

Depreciation is computed using the straight-line method at rates based on the estimated useful lives of the various classes of assets. Capital lease assets and leasehold improvements are depreciated on a straight-line basis over the shorter of the estimated useful lives of the assets or the lease term. The principal estimated useful lives are as follows:



	Range (in years)
Land improvements	3	-	25
Buildings and leasehold improvements	15	-	45
Machinery and equipment	1	-	24
Capital lease assets	3	-	5

Depreciation expense is not included in Cost of products sold, excluding depreciation and amortization and other items, but is included in Depreciation and amortization on the Statements of Consolidated Income. For 2012, 2011 and 2010, the Company recorded depreciation expense of $24.2, $22.7 and $19.4, respectively, relating to the Company's operating facilities in its Fabricated Products segment. An immaterial amount of depreciation expense was also recorded in the Company's Corporate and Other for all periods presented herein.

Property, plant and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the asset or group of assets may not be recoverable. The Company regularly assesses whether events and circumstances with the potential to trigger impairment have occurred and relies on a number of factors, including operating results, business plans, economic projections, and anticipated future cash flow, to make such assessments. The Company uses an estimate of the future undiscounted cash flows of the related asset or asset group over the estimated remaining life of such asset(s) in measuring whether the asset(s) are recoverable. Measurement of the amount of impairment, if any, is based on the difference between the carrying value of the asset(s) and the estimated fair value of such asset(s). Fair value is determined through a series of standard valuation techniques.

During 2010, the Company recorded a $2.0 impairment charge to write down the carrying amount of idled equipment to represent its estimated fair value, a $1.9 impairment charge in connection with the sale of its Greenwood, South Carolina facility and a $0.7 impairment charge relating to certain Construction in progress assets in connection with our restructuring efforts in 2009. There were no impairment charges in 2011. During 2012, the Company determined not to deploy a portion of the idled assets for future use and recorded an impairment charge of $4.4 to reflect the scrap value of such assets. Asset impairment charges are included in Other operating charges (benefits), net in the Statements of Consolidated Income and are included in the Fabricated Products segment.

Property, plant and equipment held for future development are presented as idled assets. Such assets are evaluated for impairment on a held-and-used basis. Depreciation expense is not adjusted when assets are temporarily idled.

Available for Sale Securities. The Company accounts for investments in certain marketable debt and equity securities as available for sale securities. Such securities are recorded at fair value (see “Fair Values of Financial Assets and Liabilities - Available for Sale Securities” in Note 13), with net unrealized gains and losses, net of income taxes, reflected in other comprehensive earnings as a component of Stockholders' equity. The Company's available for sale securities include securities invested in various investment funds and managed by a third-party trust in connection with the Company's deferred compensation program (see Note 8) as well as short-term commercial paper. Commercial paper with an original maturity of 90 days or less is classified as Cash and cash equivalents (see Note 2). Commercial paper with an original maturity of greater than 90 days is presented as Short-term investments on the Consolidated Balance Sheets. Securities invested in various investment funds are included in Other assets (see Note 2).

Deferred Financing Costs. Costs incurred in connection with debt financing are deferred and amortized over the estimated term of the related borrowing. Such amortization is included in Interest expense and may be capitalized as part of construction in progress (see Note 2 and Note 3).

Goodwill and Intangible Assets. Goodwill is tested for impairment on an annual basis, as well as on an interim basis, as warranted, at the time of relevant events and changes in circumstances. Intangible assets with definite lives are initially recognized at fair value and subsequently amortized over the estimated useful lives to reflect the pattern in which the economic benefits of the intangible assets are consumed. In the event the pattern cannot be reliably determined, the Company uses a straight-line amortization method. Whenever events or changes in circumstances indicate that the carrying amount of the intangible assets may not be recoverable, the intangible assets are reviewed for impairment. Beginning fourth quarter of 2011, the Company's accounting policy was to perform its annual goodwill impairment test during the fourth quarter. The Company concluded there was no impairment of the carrying value of goodwill at December 31, 2012 or December 31, 2011.

Conditional Asset Retirement Obligations (“CAROs”). The Company has CAROs at several of its fabricated products facilities. The vast majority of such CAROs consist of incremental costs that would be associated with the removal and disposal of asbestos (all of which is believed to be fully contained and encapsulated within walls, floors, roofs, ceilings or piping) at certain of the Company’s older facilities if such facilities were to undergo major renovation or be demolished. The Company, in accordance with Accounting Standards Codification ("ASC") Topic 410, Asset Retirement and Environmental Obligations, estimates incremental costs for special handling, removal and disposal costs of materials that may or will give rise to CAROs and then discounts the expected costs back to the current year using a credit-adjusted, risk-free rate. The Company recognizes liabilities and costs for CAROs even if it is unclear when or if CAROs will be triggered. When it is unclear when or if CAROs will be triggered, the Company uses probability weighting for possible timing scenarios to determine the probability-weighted amounts that should be recognized in the Company’s consolidated financial statements (see Note 13).

Self Insurance of Employee Health and Workers' Compensation Liabilities. The Company is primarily self-insured for group health insurance and workers' compensation benefits provided to employees. Self insurance liabilities are estimated for incurred-but-not-paid claims based on judgment, using the Company's historical claim data and information and analysis provided by actuarial and claim advisors, the Company's insurance carriers and other professionals. The Company accounts for accrued liability relating to workers' compensation claims on a discounted basis. The discount rates used in estimating the liabilities were 0.75% and 1.00% and the undiscounted workers' compensation liabilities were $27.3 and $24.3 at December 31, 2012 and December 31, 2011, respectively. The accrued liabilities for health insurance and workers' compensation is included in Other accrued liabilities or Long-term liabilities, as appropriate (see Note 2).

Environmental Contingencies. With respect to environmental loss contingencies, the Company records a loss contingency whenever a contingency is probable and reasonably estimable. Accruals for estimated losses from environmental remediation obligations are generally recognized at no later than the completion of the remedial feasibility study. Such accruals are adjusted as information develops or circumstances change. Costs of future expenditures for environmental remediation obligations are not discounted to their present value. Accruals for expected environmental costs are included in Other accrued liabilities or Long-term liabilities, as appropriate (see Note 2). Environmental expense relating to continuing operations is included in Cost of products sold, excluding depreciation and amortization and other items in the Statements of Consolidated Income. Environmental expense relating to non-operating locations is included in Selling, administrative, research and development, and general in the Statements of Consolidated Income.

Derivative Financial Instruments. Hedging transactions using derivative financial instruments are primarily designed to mitigate the Company's exposure to changes in prices for certain products sold and consumed by the Company and, to a lesser extent, to mitigate the Company's exposure to changes in foreign currency exchange rates. From time to time, the Company also enters into hedging arrangements in connection with financing transactions to mitigate financial risks.

The Company does not utilize derivative financial instruments for trading or other speculative purposes. The Company's derivative activities are initiated within guidelines established by management and approved by the Company's Board of Directors. Hedging transactions are executed centrally on behalf of all of the Company's business units to minimize transaction costs, monitor consolidated net exposures and allow for increased responsiveness to changes in market factors.

The Company recognizes all derivative instruments as assets or liabilities in its Consolidated Balance Sheets and measures these instruments at fair value by “marking-to-market” all of its hedging positions at each period's end (see Note 13). Because the Company does not meet the documentation requirements for hedge (deferral) accounting, unrealized and realized gains and losses associated with hedges of operational risks are reflected as a reduction or increase, respectively, in Cost of products sold (Unrealized (gains) losses on derivative instruments), and unrealized and realized gains and losses relating to hedges of financing transactions are reflected as a component of Other income (expense) (see Note 17). See Note 12 for additional information about realized and unrealized gains and losses relating to the Company's derivative financial instruments.

Fair Value Measurement. The Company applies the provisions of Accounting Standards Update (“ASU”) Topic 820, Fair Value Measurements and Disclosures, in measuring the fair value of its derivative contracts and plan assets invested by certain of the Company’s employee benefit plans (see Note 13).

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value hierarchy consists of three broad levels and are described below:


•	Level 1 — Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities.

•

Level 2 — Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly, including quoted prices for similar assets or liabilities in active markets and quoted prices for identical or similar assets or liabilities in markets that are not active; inputs other than quoted prices that are observable for the asset or liability (e.g., interest rates); and inputs that are derived principally from or corroborated by observable market data by correlation or other means.


•	Level 3 — Inputs that are both significant to the fair value measurement and unobservable.

Income Taxes. Deferred income taxes reflect the future tax effect of temporary differences between the carrying amount of assets and liabilities for financial and income tax reporting and are measured by applying statutory tax rates in effect for the year during which the differences are expected to reverse. In accordance with ASC Topic 740, Income Taxes, the Company uses a “more likely than not” threshold for recognition of tax attributes that are subject to uncertainties and measures any reserves in respect of such expected benefits based on their probability. Deferred tax assets are reduced by a valuation allowance to the extent it is more likely than not that the deferred tax assets will not be realized (see Note 7).

Earnings per Share. Basic earnings per share is computed by dividing distributed and undistributed earnings allocable to common shares by the weighted-average number of common shares outstanding during the applicable period. The basic weighted-average number of common shares outstanding during the period excludes unvested share-based payment awards. The shares owned by a voluntary employee’s beneficiary association (“VEBA”) for the benefit of certain union retirees, their surviving spouses and eligible dependents (the “Union VEBA”) that were previously subject to transfer restrictions, while treated in the Consolidated Balance Sheets as being similar to treasury stock (i.e., as a reduction in Stockholders’ equity), are included in the computation of basic weighted-average number of common shares outstanding because such shares were irrevocably issued and have full dividend and voting rights. Diluted earnings per share is calculated as the more dilutive result of computing earnings per share under: (i) the treasury stock method or (ii) the two-class method. Diluted earnings per share for 2012 was calculated under the treasury stock method. Diluted earnings per share for 2011 and 2010 was calculated under the two-class method (see Note 14).

Concentration of Credit Risk. Financial arrangements which potentially subject the Company to concentrations of credit risk consist of metal, currency, electricity and natural gas derivative contracts, certain cash-settled call options that the Company purchased in March 2010 (the “Call Options”) (see Note 3), and arrangements related to the Company's cash equivalents and short-term investments. If the market value of the Company's net commodity and currency derivative positions with certain counterparties exceeds the applicable threshold, if any, the counterparty is required to post margin by transferring cash collateral in excess of the threshold to the Company. Conversely, if the market value of these net derivative positions falls below a specified threshold, the Company is required to post margin by transferring cash collateral below the threshold to certain counterparties. At both December 31, 2012 and December 31, 2011, the Company had no margin deposits with or from its counterparties.

The Company is exposed to credit loss in the event of nonperformance by counterparties on derivative contracts used in hedging activities as well as failure of counterparties to return cash collateral previously transferred to the counterparties. The counterparties to the Company's derivative contracts are major financial institutions, and the Company does not expect nonperformance by any of its counterparties.

The Company places its cash in commercial paper, savings accounts, demand notes and money market funds. Such money market funds are with high credit quality financial institutions which invest primarily in commercial paper and time deposits of prime quality, short-term repurchase agreements, and U.S. government agency notes.

Leases. For leases that contain predetermined fixed escalations of the minimum rent, the Company recognizes the related rent expense on a straight-line basis from the date it takes possession of the property to the end of the initial lease term. The Company records any difference between the straight-line rent amounts and the amount payable under the lease as part of deferred rent, in Other accrued liabilities or Long-term liabilities, as appropriate. Deferred rent for all periods presented was not material.

Foreign Currency. Certain of the Company’s foreign subsidiaries use the local currency as its functional currency; its assets and liabilities are translated at exchange rates in effect at the balance sheet date; and its statement of operations is translated at weighted-average monthly rates of exchange prevailing during the year. Resulting translation adjustments are recorded directly to a separate component of stockholders’ equity in accordance with ASC Topic 830, Foreign Currency Matters. Where the U.S. dollar is the functional currency of a foreign facility or subsidiary, re-measurement adjustments are recorded in Other income (expense). At both December 31, 2012 and December 31, 2011, the amount of translation adjustment relating to the foreign subsidiary using local currency as its functional currency was immaterial.

New Accounting Pronouncements.

ASU No. 2011-04, Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in U.S. GAAP and IFRS (“ASU 2011-04”), was issued in May 2011. This ASU represents the converged guidance of the Financial Accounting Standards Board and the International Accounting Standards Board on fair value measurement. ASU 2011-04 sets forth common requirements for measuring fair value and for disclosing information about fair value measurements, including a consistent meaning of the term “fair value.” The provisions in this ASU are to be applied prospectively. For public entities, this ASU became effective for interim and annual periods beginning after December 15, 2011. The Company adopted the provisions of ASU 2011-04 during the interim period ended March 31, 2012. The adoption of this ASU did not have a material impact on the consolidated financial statements.

ASU No. 2011-11, Balance Sheet (Topic 210): Disclosures about Offsetting Assets and Liabilities ("ASU 2011-11"), was issued in November 2011. This ASU requires an entity to disclose information about offsetting and related arrangements to enable users of its financial statements to understand the effect of those arrangements on its financial position. An entity is required to adopt ASU 2011-11 for reporting periods beginning on or after January 1, 2013. The Company does not expect the adoption of ASU 2011-11 to have a material impact on its financial statements.

ASU No. 2012-02, Intangibles-Goodwill and Other (Topic 350): Testing Indefinite-Lived Intangible Assets for Impairment ("ASU 2012-02"), was issued in July 2012. This ASU states that an entity has the option to assess qualitative factors to determine whether the existence of events and circumstances indicates that it is more likely than not that the indefinite-lived intangible asset is impaired. If, after assessing the totality of events and circumstances, an entity concludes that it is not more likely than not that the indefinite-lived intangible asset is impaired, then the entity is not required to take further action. However, if an entity concludes otherwise, then it is required to determine the fair value of the indefinite-lived intangible asset and perform the quantitative impairment test by comparing the fair value with the carrying amount in accordance with Codification Subtopic 350-30, Intangibles-Goodwill and Other, General Intangibles Other than Goodwill. Under the guidance in this ASU, an entity also has the option to bypass the qualitative assessment for any indefinite-lived intangible asset in any period and proceed directly to performing the quantitative impairment test. An entity will be able to resume performing the qualitative assessment in any subsequent period. An entity is required to adopt ASU 2012-02 for annual and interim impairment tests performed for fiscal years beginning after September 15, 2012. The Company does not expect the adoption of ASU 2012-02 to have any impact on its financial statements.

ASU No. 2013-02, Comprehensive Income (Topic 220): Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income ("ASU 2013-02"), was issued in February 2013. This ASU does not change the current requirements for reporting net income or other comprehensive income in financial statements. However, the ASU requires an entity to provide information about the amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present, either on the face of the statement where net income is presented or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required under GAAP to be reclassified to net income in its entirety in the same reporting period. For other amounts that are not required under GAAP to be reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures required under GAAP that provide additional detail about those amounts. ASU 2013-02 is effective prospectively for reporting periods beginning after December 15, 2012 for public entities. The Company does not expect the adoption of this ASU to have a material impact on the consolidated financial statements.

- Definition

The entire disclosure for all significant accounting policies of the reporting entity.

+ References+ Details

Supplemental Balance Sheet Information

12 Months Ended

Dec. 31, 2012

Supplemental Balance Sheet Information [Abstract]

Supplemental Balance Sheet Information



	December 31, 2012		December 31, 2011
Cash and Cash Equivalents.
Cash and money market funds	$	107.9	$	49.8
Commercial paper	165.5		—
Total	$	273.4	$	49.8



Trade Receivables.
Billed trade receivables	$	124.4		$	98.9
Unbilled trade receivables — Note 1	0.2			0.9
Trade receivables, gross	124.6			99.8
Allowance for doubtful receivables	(0.8		)	(0.9		)
Trade receivables, net	$	123.8		$	98.9



Inventories.
Finished products	$	59.9	$	75.9
Work-in-process	55.5		57.5
Raw materials	53.9		58.1
Operating supplies and repairs and maintenance parts	16.7		14.2
Total	$	186.0	$	205.7



Prepaid Expenses and Other Current Assets.
Current derivative assets — Notes 12 and 13	$	3.0	$	—
Current deferred tax assets	59.5		63.0
Current portion of option premiums paid - Notes 12 and 13	0.1		0.4
Short-term restricted cash	1.3		7.8
Prepaid taxes	2.1		3.8
Prepaid expenses	4.1		3.9
Total	$	70.1	$	78.9



Property, Plant, and Equipment - Net.
Land and improvements	$	22.6		$	22.6
Buildings and leasehold improvements	50.9			45.9
Machinery and equipment	400.4			356.7
Construction in progress	20.8			24.1
Active property, plant, and equipment, gross	494.7			449.3
Accumulated depreciation	(111.4		)	(86.9		)
Active property, plant, and equipment, net	383.3			362.4
Idled equipment	1.0			5.4
Property, plant, and equipment, net	$	384.3		$	367.8



Other Assets.
Derivative assets — Notes 12 and 13	$	55.5	$	46.2
Option premiums paid — Notes 12 and 13	—		0.1
Restricted cash	10.0		10.4
Long-term income tax receivable	2.9		2.8
Deferred financing costs	11.7		7.8
Available for sale securities	5.6		4.9
Other	0.3		0.1
Total	$	86.0	$	72.3



Other Accrued Liabilities.
Current derivative liabilities — Notes 12 and 13	$	3.1	$	14.8
Current portion of option premiums received — Notes 12 and 13	0.1		0.1
Accrued book overdraft (uncleared cash disbursement)	4.7		—
Accrued income taxes and taxes payable	3.1		2.6
Accrued annual VEBA contribution	20.0		—
Accrued freight	2.2		2.4
Short-term environmental accrual — Note 11	3.0		1.2
Accrued interest	3.7		2.3
Short-term deferred revenue — Note 1	6.7		13.5
Other	5.3		4.1
Total	$	51.9	$	41.0



Long-term Liabilities.
Derivative liabilities — Notes 12 and 13	$	63.5	$	55.5
Option premiums received — Notes 12 and 13	—		0.1
Income tax liabilities	15.1		13.4
Workers’ compensation accruals	24.0		20.8
Long-term environmental accrual — Note 11	18.7		20.8
Long-term asset retirement obligations	3.8		3.8
Long-term deferred revenue - Note 1	—		3.3
Deferred compensation liability	5.8		5.1
Other long-term liabilities	3.6		3.2
Total	$	134.5	$	126.0



Long-term Debt. — Note 3
Senior notes	$	225.0	$	—
Cash convertible senior notes	155.3		148.0
Other notes payable	—		3.4
Total	$	380.3	$	151.4

Long-Term Debt

12 Months Ended

Dec. 31, 2012

Debt Disclosure [Abstract]

Long-Term Debt

Senior Notes

On May 23, 2012, the Company issued $225.0 principal amount of 8.250% Senior Notes due June 1, 2020 (the “Senior Notes”) at par. Transaction fees of $6.6 were capitalized as deferred financing costs and will be amortized on a straight-line basis over the term of the Senior Notes. Interest expense relating to the Senior Notes was $11.8 for 2012 of which $0.5 was related to the amortization of deferred financing costs. The effective interest rate of the Senior Notes is approximately 8.6% per annum, taking into account the amortization of deferred financing costs.

The Senior Notes are unsecured obligations and are guaranteed by existing and future direct and indirect subsidiaries of the Company that are borrowers or guarantors under the Company's revolving credit facility, as amended and replaced. The indenture governing the Senior Notes places limitations on the ability of the Company and certain of its subsidiaries to, among other things, incur liens, consolidate, merge or sell all or substantially all of the Company's and certain of its subsidiaries' assets, incur or guarantee additional indebtedness, prepay, redeem or repurchase certain indebtedness, make loans and investments, enter into transactions with affiliates, pay dividends and repurchase shares. In light of these restrictions, the Company has no additional material restrictions on the consolidated retained earnings or net income.

The Senior Notes are redeemable at the option of the Company in whole or part at any time on or after June 1, 2016 at an initial redemption price of 104.125% of the principal amount plus any accrued and unpaid interest, declining to a redemption price of par plus any accrued and unpaid interest on or after June 1, 2018. At any time prior to June 1, 2015, the Company may redeem up to 35% of the original principal amount of the Senior Notes with the proceeds of certain equity offerings at a redemption price of 108.250% of the principal amount, plus any accrued and unpaid interest. At any time prior to June 1, 2016, the Company may also redeem some or all of the Senior Notes at a redemption price equal to 100% of the principal amount, together with any accrued and unpaid interest, plus a “make-whole premium.”

Holders of the Senior Notes have the right to require the Company to repurchase the Senior Notes at a price equal to 101% of the principal amount plus any accrued and unpaid interest following a change of control. A change of control include (i) certain ownership changes, (ii) certain recapitalizations, mergers and dispositions, (iii) certain changes in the composition of the Board of Directors of the Company, and (iv) shareholders' approval of any plan or proposal for the liquidation or dissolution of the Company. The Company may also be required to offer to repurchase the Senior Notes at a price of par with the proceeds of certain asset sales.

See “Fair Values of Financial Assets and Liabilities - All Other Financial Assets and Liabilities” in Note 13 for information relating to the estimated fair value of the Senior Notes.

Cash Convertible Senior Notes

Convertible Notes. In March 2010, the Company issued $175.0 principal amount of 4.5% Cash Convertible Senior Notes due April 1, 2015 (the "Convertible Notes"). The Convertible Notes are unsecured obligations of the Company. The Company accounts for the cash conversion feature of the Convertible Notes (the “Bifurcated Conversion Feature”) as a separate derivative instrument with the fair value on the issuance date equaling the original issue discount for purposes of accounting for the debt component of the Convertible Notes. Additionally, the initial purchasers' discounts and transaction fees of $5.9 were capitalized as deferred financing costs. The effective interest rate of the Convertible Notes is approximately 11% per annum, taking into account the amortization of the original issuance discount and deferred financing costs.

The following tables provide additional information regarding the Convertible Notes:

Statements of Consolidated Stockholders' Equity (Parenthetical) (Retained Earnings, USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash dividends declared on common stock (per share)	$ 1.00	$ 0.96	$ 0.96

Statement of Consolidated Cash Flows (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011
Cash flows from investing activities:
Cash received in the acquisition	$ 4.9