Kaiser Aluminum (KALU) 10-Q 24 Jul 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 21, 2014
Document and Entity Information [Abstract]	'	'
Entity Registrant Name	'Kaiser Aluminum Corp	'
Entity Central Index Key	'0000811596	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Amendment Flag	'false	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	17,871,808

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$174.20	$169.50
Short-term investments	127.2	129.5
Receivables:	'	'
Trade, less allowance for doubtful receivables of $0.8 at June 30, 2014 and December 31, 2013	123.1	119.8
Other	11	13.4
Inventories	198.1	214.4
Prepaid expenses and other current assets	135.5	44.2
Total current assets	769.1	690.8
Property, plant, and equipment – net	441.4	429.3
Net assets of VEBAs	422.2	406
Deferred tax assets – net (including deferred tax liability relating to the VEBAs of $158.4 at June 30, 2014 and $152.4 at December 31, 2013)	45.8	69.1
Intangible assets – net	32.9	33.7
Goodwill	37.2	37.2
Other assets	24	104.8
Total	1,772.60	1,770.90
Current liabilities:	'	'
Accounts payable	72.1	62.9
Accrued salaries, wages, and related expenses	33.8	42.7
Other accrued liabilities	115.1	44.8
Current portion of long-term debt	167.9	0
Short-term capital lease	0.1	0.2
Total current liabilities	389	150.6
Deferred tax liability	1.2	1.2
Long-term liabilities	63.7	146.4
Long-term debt	225	388.5
Total liabilities	678.9	686.7
Commitments and contingencies – Note 7	'	'
Stockholders’ equity:	'	'
Preferred stock, 5,000,000 shares authorized at both June 30, 2014 and December 31, 2013; no shares were issued and outstanding at June 30, 2014 and December 31, 2013	0	0
Common stock, par value $0.01, 90,000,000 shares authorized at both June 30, 2014 and at December 31, 2013; 21,236,249 shares issued and 17,932,785 shares outstanding at June 30, 2014; 21,103,700 shares issued and 18,147,017 shares outstanding at December 31, 2013	0.2	0.2
Additional paid in capital	1,026	1,023.10
Retained earnings	261.4	233.8
Treasury stock, at cost, 3,303,464 shares at June 30, 2014 and 2,956,683 shares at December 31, 2013, respectively	-176.2	-152.2
Accumulated other comprehensive loss	-17.7	-20.7
Total stockholders’ equity	1,093.70	1,084.20
Total	$1,772.60	$1,770.90

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified
Receivables:	'	'
Allowance for doubtful receivables	$0.80	$0.80
Deferred tax liabilities relating to the VEBAs	$158.40	$152.40
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	21,236,249	21,103,700
Common stock, shares outstanding	17,932,785	18,147,017
Treasury stock, shares	3,303,464	2,956,683

Statements_of_Consolidated_Inc

Statements of Consolidated Income (USD $)	3 Months Ended				6 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Net sales	$344.10		$328.90		$679.20		$666.30
Cost of products sold:	'		'		'		'
Cost of products sold, excluding depreciation and amortization and other items	275.5		261.5		558.4		525.1
Unrealized (gains) losses on derivative instruments	-1.6		4.2		-3.6		4.9
Depreciation and amortization	7.7		7		15.1		14
Selling, administrative, research and development, and general	22		21.8		42.3		43.5
Net periodic pension benefit income relating to VEBAs (includes accumulated other comprehensive income reclassifications related to VEBA of $2.0 and $1.4 for the quarters ended June 30, 2014 and June 30, 2013, respectively, and $4.5 and $2.8 for the six months ended June 30, 2014 and June 30, 2013, respectively)	-6.1		-5.7		-11.7		-11.3
Total selling, administrative, research and development, and general	15.9		16.1		30.6		32.2
Other operating charges, net	-0.2		0		-0.2		0
Total costs and expenses	297.7		288.8		600.7		576.2
Operating income	46.4		40.1		78.5		90.1
Other (expense) income:	'		'		'		'
Interest expense	-9.2		-9		-18		-18.3
Other income (expense), net (includes accumulated other comprehensive income reclassifications for realized gains on available for sale securities of $0.1 and $0.2 for the quarters ended June 30, 2014 and June 30, 2013, respectively, and $0.2 and $0.6 for the six months ended June 30, 2014 and June 30, 2013, respectively)	1.8		-0.8		3.7		0.2
Income before income taxes	39		30.3		64.2		72
Income tax provision (includes aggregate income tax expense from reclassification items of $(0.7) and $(0.4) for the quarters ended June 30, 2014 and June 30, 2013, respectively, and $(1.6) and $(0.8) for the six months ended June 30, 2014 and June 30, 2013, respectively)	-14.5		-11.7		-23.9		-19.9
Net income	$24.50		$18.60		$40.30		$52.10
Earnings per common share, Basic:	'		'		'		'
Net income per share	$1.38		$0.99		$2.25		$2.73
Earnings per common share, Diluted:	'		'		'		'
Net income per share	$1.33		$0.98		$2.18		$2.70
Weighted-average number of common shares outstanding (in thousands):	'		'		'		'
Basic	17,841	[1]	18,742	[1]	17,889	[1]	19,027	[1]
Diluted	18,458	[2]	18,945	[2]	18,512	[2]	19,256	[2]
[1]	The basic weighted-average number of common shares outstanding during the period excludes non-vested common shares, restricted stock units, performance shares and market-based shares.
[2]	The diluted weighted-average number of common shares outstanding during the periods were calculated using the treasury method.

Statements_of_Consolidated_Inc1

Statements of Consolidated Income Statements of Consolidated Income (Parenthetical) (USD $)	3 Months Ended				6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Income Statement [Abstract]	'		'		'		'
Accumulated other comprehensive income reclassifications related to VEBA adjustments	$2		$1.40		$4.50		$2.80
Reclassification of unrealized gain upon sale of available for sale securities	-0.1	[1]	-0.2	[1]	-0.2	[1]	-0.6	[1]
Other comprehensive income reclassification adjustment, tax	($0.70)		($0.40)		($1.60)		($0.80)
[1]	Amounts reclassified out of Accumulated other comprehensive income relating to sales of available for sale securities were included as a component of Other income (expense), net. The Company uses the specific identification method to determine the amount reclassified out of accumulated other comprehensive income.

Statements_of_Consolidated_Com

Statements of Consolidated Comprehensive Income (USD $)	3 Months Ended				6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Statement of Comprehensive Income [Abstract]	'		'		'		'
Net income	$24.50		$18.60		$40.30		$52.10
Reclassification adjustments:	'		'		'		'
Amortization of net actuarial (gain) loss	-0.6	[1]	0.4	[1]	-0.9	[1]	0.7	[1]
Amortization of prior service cost	2.6	[1]	1	[1]	5.4	[1]	2.1	[1]
Other comprehensive income relating to VEBAs	2		1.4		4.5		2.8
Available for sale securities:	'		'		'		'
Unrealized gain on available for sale securities	0.2		0.2		0.3		0.5
Reclassification adjustments:	'		'		'		'
Reclassification of unrealized gain upon sale of available for sale securities	-0.1	[2]	-0.2	[2]	-0.2	[2]	-0.6	[2]
Other comprehensive income (loss) relating to available for sale securities	0.1		0		0.1		-0.1
Foreign currency translation adjustment	-0.1		0.4		0.1		0.8
Other comprehensive income, before tax	2		1.8		4.7		3.5
Income tax expense related to items of other comprehensive income	0.1	[3]	-0.5	[3]	-1.7	[3]	-1	[3]
Other comprehensive income, net of tax	2.1		1.3		3		2.5
Comprehensive income	$26.60		$19.90		$43.30		$54.60
[1]	Amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments were included as a component of Net periodic pension benefit income relating to VEBAs.
[2]	Amounts reclassified out of Accumulated other comprehensive income relating to sales of available for sale securities were included as a component of Other income (expense), net. The Company uses the specific identification method to determine the amount reclassified out of accumulated other comprehensive income.
[3]	Income tax amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments and sales of available for sale securities were included as a component of Income tax provision.

Statement_of_Consolidated_Stoc

Statement of Consolidated Stockholders' Equity (USD $)	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
In Millions, except Share data, unless otherwise specified
Beginning balance at Dec. 31, 2013	$1,084.20	$0.20	$1,023.10	$233.80	($152.20)	($20.70)
Beginning balance, shares at Dec. 31, 2013	18,147,017	18,147,017	'	'	'	'
Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Net income	40.3	'	'	40.3	'	'
Other comprehensive income, net of tax	3	'	'	'	'	3
Issuance of non-vested shares to employees, shares	'	118,638	'	'	'	'
Issuance of common shares to non-employee directors, shares	'	2,548	'	'	'	'
Issuance of common shares to non-employee directors	0.2	'	0.2	'	'	'
Issuance of common shares to employees upon vesting of restricted stock units and performance shares, shares	'	44,895	'	'	'	'
Cancellation of employee non-vested shares	'	-526	'	'	'	'
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares	'	-33,006	'	'	'	'
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	-2.4	'	-2.4	'	'	'
Repurchase of common stock, shares	-346,781	-346,781	'	'	'	'
Repurchase of common stock	-24	'	'	'	-24	'
Cash dividends on common stock ($0.70 per share)	-12.8	'	'	-12.8	'	'
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0.8	'	0.8	'	'	'
Amortization of unearned equity compensation	4.3	'	4.3	'	'	'
Dividends on unvested equity awards that were canceled	0.1	'	'	0.1	'	'
Ending balance at Jun. 30, 2014	$1,093.70	$0.20	$1,026	$261.40	($176.20)	($17.70)
Ending balance, shares at Jun. 30, 2014	17,932,785	17,932,785	'	'	'	'

Statement_of_Consolidated_Stoc1

Statement of Consolidated Stockholders' Equity Statement of Consolidated Stockholders' Equity (Parenthetical) (Retained Earnings, USD $)	6 Months Ended
	Jun. 30, 2014
Retained Earnings	'
Cash dividend declared per common share	$0.70

Statement_of_Consolidated_Cash

Statement of Consolidated Cash Flows (USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013
Cash flows from operating activities:	'		'
Net income	$40.30		$52.10
Adjustments to reconcile net income to net cash provided by operating activities:	'		'
Depreciation of property, plant and equipment	14.3		13.1
Amortization of definite-lived intangible assets	0.8		0.9
Amortization of debt discount and debt issuance costs	5.8		5.4
Deferred income taxes	22.4		26.1
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	-0.8		-0.9
Non-cash equity compensation	4.5		4.7
Non-cash unrealized (gains) losses on derivative positions	4.9		-5.4
Non-cash impairment charges	0.2		0
Losses on disposition of property, plant and equipment	0.1		0.1
Gain on disposition of available for sale securities	0		-0.3
Non-cash net periodic pension benefit income relating to VEBAs	-11.7		-11.3
Other non-cash changes in assets and liabilities	0.3		-2.5
Changes in operating assets and liabilities:	'		'
Trade and other receivables	-0.9		-4.5
Inventories	16.3		-16.9
Prepaid expenses and other current assets1	-2.1	[1]	-1.7
Accounts payable	12.2		9.1
Accrued liabilities	-10.2	[1]	-0.2
Annual variable cash contributions to VEBAs	-16		-20
Payable to affiliate	0		-7.9
Long-term assets and liabilities, net1	0.7	[1]	-1.8
Net cash provided by operating activities	71.3		48.9
Cash flows from investing activities:	'		'
Capital expenditures	-30.1		-26
Purchase of available for sale securities	-23.4		-98.2
Proceeds from disposition of available for sale securities	25		135.7
Change in restricted cash	0		0.7
Net cash (used in) provided by investing activities	-28.5		12.2
Cash flows from financing activities:	'		'
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0.8		0.9
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	-2.4		-2.2
Repurchase of common stock	-23.7		-39.9
Cash dividend paid to stockholders	-12.8		-11.6
Net cash used in financing activities	-38.1		-52.8
Net increase in cash and cash equivalents during the period	4.7		8.3
Cash and cash equivalents at beginning of period	169.5		273.4
Cash and cash equivalents at end of period	$174.20		$281.70
[1]	Excludes the reclassification of derivatives relating to the Convertible Notes from long-term to current as the amounts have no impact on cash flow - see Note 3 and Note 9.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Summary of Significant Accounting Policies
	This Quarterly Report on Form 10-Q (this "Report") should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2013.
	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 11 for additional information regarding the Company’s reportable segment and its other business units.
	Principles of Consolidation and Basis of Presentation. The accompanying unaudited 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”) applicable for interim periods and, therefore, do not include all information and footnotes required by GAAP for complete financial statements. In management’s opinion, all adjustments (which include normal recurring adjustments) considered necessary for a fair presentation have been included. The results of operations for the Company’s interim periods are not necessarily indicative of the results of operations that may be achieved for the entire 2014 fiscal year. The financial information as of December 31, 2013 is derived from the Company’s audited consolidated financial statements and footnotes for the year ended December 31, 2013 included in the Company’s Annual Report on Form 10-K.
	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.
	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. During the quarter and six months ended June 30, 2014, the Company decremented a prior year, higher cost LIFO layer which resulted in charges of $0.6 and $2.4, respectively. The excess of current cost over the stated LIFO value of inventory at June 30, 2014 and December 31, 2013 was $17.4 and $0.4, respectively. 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 June 30, 2014 and December 31, 2013 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 on 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 $0.8 and $0.7 during the quarters ended June 30, 2014 and June 30, 2013, respectively. The amount of interest expense capitalized as construction in progress was $1.9 and $1.1 for the six months ended June 30, 2014 and June 30, 2013, 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. For the quarters ended June 30, 2014 and June 30, 2013, the Company recorded depreciation expense of $7.3 and $6.5, respectively, relating to the Company’s operating facilities in its Fabricated Products segment. For the six months ended June 30, 2014 and June 30, 2013, the Company recorded depreciation expense of $14.1 and $13.0, respectively, relating to the Company’s operating facilities in its Fabricated Products segment. An immaterial amount of depreciation expense was also recorded relating to the Company’s All Other business unit for all periods presented in this Report.
	New Accounting Pronouncements. Accounting Standards Update ASU No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. (“ASU 2013-11”), was issued in July 2013. ASU 2013-11 requires an entity to present in the financial statements an unrecognized tax benefit, or a portion of an unrecognized tax benefit, as a reduction to a deferred tax asset resulting from a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. However, when the above situation is not available at the reporting date or the tax law of the applicable jurisdiction does not require the entity to use the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. An entity is required to adopt ASU 2013-11 for annual and interim periods beginning after December 15, 2013. The Company’s adoption of ASU 2013-11 in the first quarter of 2014 did not have a material impact on its financial statements.
	ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), was issued in May 2014. ASU 2014-09 requires an entity to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve this core principle, the guidance provides that an entity should apply the following steps: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the entity satisfies a performance obligation. The Company expects to adopt ASU 2014-09 for the fiscal year ending December 31, 2016 and the Company will continue to assess the impact on its financial statements.
	ASU No. 2014-12, Compensation-Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period - Consensus of the FASB Emerging Issues Task Force (“ASU 2014-12”), was issued in June 2014. ASU 2014-12 requires an entity to treat a performance target that affects vesting and that could be achieved after the requisite service period as a performance condition. The performance target should not be reflected in estimating the grant-date fair value of the award. Additionally, compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved, and should represent the compensation cost attributable to the period(s) for which the requisite service has already been rendered; if the performance target becomes probable of being achieved before the end of the requisite service period, then the remaining unrecognized compensation cost should be recognized prospectively over the remaining requisite service period. Finally, the total amount of compensation cost recognized during and after the requisite service period should reflect the number of awards that are expected to vest, and should be adjusted to reflect those awards that ultimately vest. An entity is required to adopt ASU 2014-12 for annual and interim periods beginning after December 15, 2015. The Company does not expect the adoption of ASU 2014-12 to have a material impact on its financial statements.

Supplemental_Balance_Sheet_Inf

Supplemental Balance Sheet Information	6 Months Ended
	Jun. 30, 2014
Supplemental Balance Sheet Information [Abstract]	'
Supplemental Balance Sheet Information	'
	Supplemental Balance Sheet Information
		June 30, 2014			December 31, 2013
	Cash and Cash Equivalents.
	Cash and money market funds	$	69.7		$	57.7
	Commercial paper	104.5			111.8
	Total	$	174.2		$	169.5
	Trade Receivables.
	Billed trade receivables	$	123.7		$	120.2
	Unbilled trade receivables	0.2			0.4
	Trade receivables, gross	123.9			120.6
	Allowance for doubtful receivables	(0.8		)	(0.8		)
	Trade receivables, net	$	123.1		$	119.8
	Inventories.
	Finished products	$	60.4		$	72.5
	Work-in-process	64.3			75.9
	Raw materials	53.3			47.2
	Operating supplies and repair and maintenance parts	20.1			18.8
	Total	$	198.1		$	214.4
	Prepaid Expenses and Other Current Assets.
	Current derivative assets – Notes 8 and 9	$	90.3		$	2
	Current deferred tax assets	36.7			36.7
	Short-term restricted cash	0.3			0.3
	Prepaid taxes	1.8			—
	Other	6.4			5.2
	Total	$	135.5		$	44.2
	Property, Plant and Equipment - Net.
	Land and improvements	$	22.8		$	22.6
	Buildings and leasehold improvements	54.7			53
	Machinery and equipment	491.2			425.6
	Construction in progress	24.7			66
	Active property, plant and equipment, gross	593.4			567.2
	Accumulated depreciation	(152.0		)	(137.9		)
	Total	$	441.4		$	429.3
	Other Assets.
	Derivative assets – Notes 8 and 9	$	0.3		$	79.8
	Restricted cash	9.3			9.3
	Deferred financing costs	6.7			8.9
	Deferred compensation plan assets	7.4			6.5
	Other	0.3			0.3
	Total	$	24		$	104.8
	Other Accrued Liabilities.
	Current derivative liabilities – Notes 8 and 9	$	89.5		$	1.8
	Uncleared cash disbursements	9.1			9.6
	Accrued income taxes and taxes payable	6.3			4.6
	Accrued annual VEBA contribution	—			16
	Short-term environmental accrual – Note 7	3.6			2.8
	Accrued interest	3.6			3.7
	Other	3			6.3
	Total	$	115.1		$	44.8
	Long-Term Liabilities.
	Derivative liabilities – Notes 8 and 9	$	0.5		$	84.3
	Income tax liabilities	5.2			5
	Workers’ compensation accruals	24.4			23.3
	Long-term environmental accrual – Note 7	18.6			20
	Long-term asset retirement obligations	4.3			4
	Deferred compensation liability	7.7			7
	Long-term capital lease	0.1			0.1
	Other long-term liabilities	2.9			2.7
	Total	$	63.7		$	146.4
	Long-Term Debt — Note 3.
	Senior notes	$	225		$	225
	Cash convertible senior notes	—			163.5
	Total	$	225		$	388.5

LongTerm_Debt_and_Credit_Facil

Long-Term Debt and Credit Facility	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Long-Term Debt	'
	Debt and Credit Facility
	Senior Notes
	In May 2012, the Company issued $225.0 principal amount of 8.25% Senior Notes due June 1, 2020 (the “Senior Notes”) at 100% of the principal amount. Interest expense, including amortization of deferred financing costs, relating to the Senior Notes was $4.9 and $9.7 for the quarter and six months ended June 30, 2014, respectively. Interest expense, including amortization of deferred financing costs, relating to the Senior Notes was $4.8 and $9.6 for the quarter and six months ended June 30, 2013, respectively. A portion of the interest relating to the Senior Notes is capitalized as Construction in progress. See Note 3 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report Form 10-K for the year ended December 31, 2013 for additional information regarding the Senior Notes.
	Cash Convertible Senior Notes
	Convertible Notes. In March 2010, the Company issued $175.0 principal amount of 4.50% Cash Convertible Senior Notes due April 1, 2015 (the “Convertible Notes”). The Convertible Notes are unsecured obligations of the Company. The Convertible Notes are not convertible into the Company's common stock or any other securities, but instead will be settled in cash. The Company accounts for the cash conversion feature of the Convertible Notes as a separate derivative instrument (the “Bifurcated Conversion Feature”) 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. The following tables provide additional information regarding the Convertible Notes:
		June 30, 2014			December 31, 2013
	Principal amount	$	175		$	175
	Less: unamortized issuance discount	(7.1		)	(11.5		)
	Carrying amount, net of discount	$	167.9		$	163.5
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014		2013
	Contractual coupon interest	$	1.9		$	1.9		$	3.9	$	3.9
	Amortization of discount	2.3			2.1			4.4		4
	Amortization of deferred financing costs	0.3			0.3			0.6		0.6
	Total interest expense1	$	4.5		$	4.3		$	8.9	$	8.5
	____________
	1	A portion of the interest relating to the Convertible Notes is capitalized as Construction in progress.
	The Convertible Notes’ conversion rate is subject to adjustment based on the occurrence of certain events, including, but not limited to, the payment of quarterly cash dividends on the Company’s common stock in excess of $0.24 per share. As of June 30, 2014 the conversion rate was 20.8549 shares per $1,000 principal amount of the Convertible Notes and the equivalent conversion price was approximately $47.95 per share, reflecting cumulative adjustments for quarterly dividends paid in excess of $0.24 per share.
	Holders may convert their Convertible Notes at any time on or after January 1, 2015 and, in certain limited circumstances, before January 1, 2015. Pursuant to one of the early conversion provisions, if the Company's closing stock price exceeds 130% of the conversion price for 20 trading days during the final 30 consecutive trading days of a quarter, holders may convert the Convertible Notes during the following quarter. Under this provision, holders were able to convert during the second quarter of this year, and an immaterial amount of Convertible Notes was presented for conversion during the second quarter of 2014 for settlement in the third quarter. This provision was also triggered at June 30, 2014, allowing holders to present Convertible Notes for early conversion during the third quarter of 2014.
	During the second quarter of 2014, the Convertible Notes were reclassified as current liability and the carrying amount, net of discount, was included in the Consolidated Balance Sheet as Current portion of long-term debt as of June 30, 2014.
	Convertible Note Hedge Transactions. In March 2010, the Company purchased cash-settled call options (the “Call Options”) that have an exercise price equal to the conversion price of the Convertible Notes and an expiration date that is the same as the maturity or on the earlier conversion date of the Convertible Notes. If the Company exercises the Call Options, the aggregate amount of cash it would receive from the counterparties to the Call Options will cover the aggregate amount of cash that the Company would be required to pay to the holders of the converted Convertible Notes, less the principal amount thereof. Contemporaneous with the purchase of the Call Options, the Company also sold net-share-settled warrants (the “Warrants”) which are exercisable on a prorated basis for 120 trading days commencing July 1, 2015 relating to approximately 3.6 million shares of the Company’s common stock. The Call Option and the Warrants have anti-dilution provisions substantially similar to the Convertible Notes. At June 30, 2014, the exercise prices were $47.95 per share and $60.89 per share for the Call Options and the Warrants, respectively, reflecting cumulative adjustments for quarterly dividends paid in excess of $0.24 per share.
	See Note 3 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information regarding the Convertible Notes, the Call Options and the Warrants.
	See “Fair Values of Financial Assets and Liabilities - All Other Financial Assets and Liabilities” in Note 9 for information relating to the estimated fair value of the Senior Notes and Convertible Notes.
	Revolving Credit Facility
	The Company’s credit agreement with JPMorgan Chase Bank, N.A., as administrative agent, and the other financial institutions party thereto (the “Revolving Credit Facility”) provides the Company with a $300.0 funding commitment through September 30, 2016. The Company had $258.3 of borrowing availability under the Revolving Credit Facility at June 30, 2014, based on the borrowing base determination then in effect. At June 30, 2014, there were no borrowings under the Revolving Credit Facility and $7.4 was being used to support outstanding letters of credit, leaving $250.9 of net borrowing availability. The interest rate applicable to any overnight borrowings under the Revolving Credit Facility would have been 4.0% at June 30, 2014.
	See Note 3 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information regarding the Revolving Credit Facility.

Income_Tax_Matters

Income Tax Matters	6 Months Ended
	Jun. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Tax Matters	'
	Income Tax Matters
	The provision for incomes taxes, for each period presented, consisted of the following:
		Quarter Ended				Six Months Ended
		June 30,				June 30,
		2014		2013		2014		2013
	Domestic	$	13.9	$	11.1	$	23	$	26.5
	Foreign	0.6		0.6		0.9		(6.6		)
	Total	$	14.5	$	11.7	$	23.9	$	19.9
	The income tax provision for the quarters ended June 30, 2014 and June 30, 2013 was $14.5 and $11.7, reflecting an effective tax rate of 37.0% and 38.6%, respectively. There was no material difference between the effective tax rate and the projected blended statutory tax rate for the quarter ended June 30, 2014.
	The difference between the effective tax rate and the projected blended statutory tax rate for the quarter ended June 30, 2013 was primarily the result of an increase in unrecognized tax benefits, including interest and penalties, of $0.3, resulting in a 0.9% increase in the effective tax rate.
	The income tax provision for the six months ended June 30, 2014 and June 30, 2013 was $23.9 and $19.9, reflecting an effective tax rate of 37.2% and 27.7%, respectively. There was no material difference between the effective tax rate and the projected blended statutory tax rate for the six months ended June 30, 2014.
	The difference between the effective tax rate and the projected blended statutory tax rate for the six months ended June 30, 2013 was the result of a decrease in unrecognized tax benefits, including interest and penalties, of $7.2, resulting in a 10.0% decrease in the effective tax rate. The decrease in unrecognized tax benefits was primarily a result of an audit settlement with the Canada Revenue Agency Competent Authority on February 28, 2013 for the 1998-2004 tax years which resulted in a cash tax benefit to the Company of $7.7, of which $7.2 has been received as of June 30, 2014. In addition, during the third quarter of 2013, the Company signed an advance pricing agreement with the Canada Revenue Agency, which resulted in an additional cash tax benefit of $2.8, which is expected to be refunded within the next 12 months.
	The Company’s gross unrecognized benefits relating to uncertain tax positions was $3.8 at both June 30, 2014 and December 31, 2013, of which, $2.7 will go through the Company’s income tax provision and thus impact the effective tax rate at both June 30, 2014 and December 31, 2013, if and when the gross unrecognized tax benefits are recognized.
	The Company expects its gross unrecognized tax benefits to be reduced by $1.8 within the next 12 months.
	See Note 6 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information regarding income taxes.

Employee_Benefits

Employee Benefits	6 Months Ended
	Jun. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Employee Benefits	'
	Employee Benefits
	Pension and Similar Benefit Plans. The Company has provided contributions to (i) multi-employer pension plans sponsored by the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union AFL-CIO, CLC (“USW”) and International Association of Machinists and certain other unions at certain of the Company’s production facilities, (ii) defined contribution 401(k) savings plans for hourly bargaining unit employees and salaried and certain hourly non-bargaining unit employees, (iii) a defined benefit plan for salaried employees at the Company’s London, Ontario facility, and (iv) a non-qualified, unfunded, unsecured plan of deferred compensation for key employees who would otherwise suffer a loss of benefits under the Company’s defined contribution plan. See Note 7 and Note 8 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information with respect to the Company’s benefit plans.
	VEBA Postretirement Medical Obligations. Certain retirees receive medical coverage through participation in a voluntary employees beneficiary association (“VEBA”) for the benefit of certain union retirees, their surviving spouses and eligible dependents (the “Union VEBA”) or a VEBA that provides benefits for certain other eligible retirees, their surviving spouses and eligible dependents (the “Salaried VEBA” and, together with the Union VEBA, the “VEBAs”). The Union VEBA is managed by four trustees, two of which are appointed by the Company and two of which are appointed by the USW. Its assets are managed by an independent fiduciary. The Salaried VEBA is managed by trustees who are independent of the Company.
	The Company has no ownership interest in the assets of the VEBAs nor any obligation to fund their liabilities. The benefits paid by the VEBAs to the plan participants are made at the sole discretion of the respective VEBA trustees and are outside the Company's control. The Company’s only financial obligations to the VEBAs are (i) an annual variable cash contribution (described below) and (ii) reimbursement of annual administrative expenses of the VEBAs up to $0.3 in the aggregate. Nevertheless, the Company accounts for the VEBAs as defined benefit postretirement plans with the maximum benefits payable equal to the total of the current VEBA assets and any future variable contributions from the Company and earnings thereon.
	Under this accounting treatment, the funding status of the VEBAs is reflected as a net asset or liability on the Company's Consolidated Balance Sheets, but such net asset or liability has no impact on the Company's cash flow or liquidity. The only impact that the VEBAs have on the Company’s cash flow or liquidity is with respect to the Company's obligations to make an annual variable cash contribution and to reimburse a portion of the VEBAs’ administrative expenses. The amount of annual variable cash contribution to be made by the Company is determined as follows: 10% of the first $20.0 of annual cash flow (as defined; in general terms, the principal elements of cash flow are earnings before interest expense, provision for income taxes, and depreciation and amortization less cash payments for, among other things, interest, income taxes, and capital expenditures), plus 20% of annual cash flow (as defined) in excess of $20.0. Such payments may not exceed $20.0 annually, and payments are allocated between the Union VEBA and the Salaried VEBA at 85.5% and 14.5%, respectively. Amounts owing by the Company to the VEBAs are recorded on the Company’s Consolidated Balance Sheets at the end of each year in Other accrued liabilities (until paid in cash), with a corresponding increase in Net assets of VEBAs, a decrease in Net liabilities of VEBAs, or a combination thereof. The annual variable cash contributions with respect to 2013 and 2012 totaled $16.0 and $20.0 at December 31, 2013 and December 31, 2012, respectively, and were paid during the subsequent first quarters.
	Components of Net Periodic Pension Benefit (Income) Cost. The Company’s results of operations included the following impacts associated with the VEBAs and the Canadian defined benefit plan: (i) charges for service rendered by employees; (ii) a charge for accretion of interest; (iii) a benefit for the return on plan assets; and (iv) amortization of net gains or losses on assets, prior service costs associated with plan amendments and actuarial differences. Net periodic pension benefit cost related to the Canadian defined benefit plan was not material for the quarter and six months ended June 30, 2014 and June 30, 2013. The following table presents the components of net periodic pension benefit income for the VEBAs and charges relating to all other employee benefit plans for the quarter and six months ended June 30, 2014 and June 30, 2013:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	VEBAs:
	Service cost	$	0.5		$	0.7		$	1.1		$	1.3
	Interest cost	4.2			3.7			8.3			7.3
	Expected return on plan assets	(12.8		)	(11.5		)	(25.6		)	(22.7		)
	Amortization of prior service cost	2.6			1			5.4			2.1
	Amortization of net actuarial (gain) loss	(0.6		)	0.4			(0.9		)	0.7
	Total net periodic pension benefit (income) expense relating to VEBAs	(6.1		)	(5.7		)	(11.7		)	(11.3		)
	Deferred compensation plan	0.4			—			0.6			0.4
	Defined contribution plans	1.5			1.3			5.5			5.3
	Multiemployer pension plans	0.9			0.9			1.8			1.7
	Total	$	(3.3	)	$	(3.5	)	$	(3.8	)	$	(3.9	)
	The following table presents the allocation of the (income) charges detailed above, by reportable segment and business unit (see Note 11):
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Fabricated Products	$	2.3		$	2		$	6.9		$	6.6
	All Other	(5.6		)	(5.5		)	(10.7		)	(10.5		)
	Total	$	(3.3	)	$	(3.5	)	$	(3.8	)	$	(3.9	)
	For all periods presented, the net periodic pension benefit income relating to the VEBAs are included as Net periodic pension benefit income relating to VEBAs within All Other. Further, substantially all of the Fabricated Products segment’s employee benefits related charges are in Cost of products sold, excluding depreciation and amortization and other items with the remaining balance in Selling, administrative, research and development, and general.
	See Note 7 of Notes to Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information with respect to the VEBAs and key assumptions used with respect to the Company’s pension plans and key assumptions made in computing the net obligation of each VEBA.

Employee_Incentive_Plans

Employee Incentive Plans	6 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Employee Incentive Plans	'
	Employee Incentive Plans
	Short-Term Incentive Plans (“STI Plans”)
	The Company has annual short-term incentive compensation plans for senior management and certain other employees payable at the Company’s election in cash, shares of common stock, or a combination of cash and shares of common stock. Amounts earned under the 2013 STI plan were based primarily on the economic value added (“EVA”) of the Company’s Fabricated Products business, adjusted for certain safety and individual performance factors. EVA, as defined by the Company’s STI Plans, is 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, measured over a one-year period. Amounts, if any, that will be earned under the 2014 STI plan are based on the Company’s adjusted earnings before interest, taxes, depreciation and amortization (“Adjusted EBIDTA”), modified for certain safety, quality, delivery, cost and individual performance factors. The Adjusted EBITDA targets under the 2014 STI plan were determined based on the EVA of the Company’s Fabricated Products business. Most of the Company’s production facilities have similar programs for both hourly and salaried employees.
	Total costs relating to STI Plans were recorded as follows, for each period presented:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Cost of products sold, excluding depreciation and amortization and other items	$	1.4		$	1.3		$	2.5			$	2.4
	Selling, administrative, research and development, and general	3.2			3.5			4.5				6.5
	Total costs recorded in connection with STI Plans	$	4.6		$	4.8		$	7			$	8.9
	The following table presents the allocation of the charges detailed above, by segment:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Fabricated Products	$	3.5		$	3.3		$	5.4			$	6.2
	All Other	1.1			1.5			1.6				2.7
	Total costs recorded in connection with STI Plans	$	4.6		$	4.8		$	7			$	8.9
	Long-Term Incentive Programs (“LTI Programs”)
	General. Officers and other key employees of the Company or one or more of its subsidiaries, as well as directors of the Company, are eligible to participate in the Kaiser Aluminum Corporation Amended and Restated 2006 Equity and Performance Incentive Plan (as amended, the “Equity Incentive Plan”). Subject to certain adjustments that may be required from time to time to prevent dilution or enlargement of the rights of participants under the Equity Incentive Plan, a total of 2,722,222 common shares have been authorized for issuance under the Equity Incentive Plan. At June 30, 2014, 698,231 common shares were available for additional awards under the Equity Incentive Plan.
	Non-vested Common Shares, Restricted Stock Units and Performance Shares. The Company grants non-vested common shares to its non-employee directors, executive officers and other key employees. The Company also grants restricted stock units to certain employees. The restricted stock units have rights similar to the rights of non-vested common shares, and the employee will receive one common share for each restricted stock unit upon the vesting of the restricted stock unit. In addition to non-vested common shares and restricted stock units, the Company also grants performance shares to executive officers and other key employees. Performance shares granted prior to 2014 are subject to performance requirements pertaining to the Company’s EVA as set forth in each year’s LTI Program, measured over a three-year performance period. EVA, as defined in the Company’s LTI Programs, is 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. The number of performance shares, if any, that will ultimately vest under the prior year programs and result in the issuance of common shares depends on the average annual EVA achieved for the specified three-year performance period. Performance shares granted in 2014 are subject to market-based requirements pertaining to the Company’s total shareholder return (“TSR”) over a three-year performance period compared to the TSR of a specified group of peer companies. The number of performance shares, if any, that will ultimately vest under the 2014-2016 LTI program and result in the issuance of common shares depends on the percentile ranking of the Company’s TSR compared to the group of peer companies.
	During the first quarter of 2014, a portion of the performance shares granted under the 2011-2013 LTI program vested (see “Summary of Activity” below). The vesting of performance shares and resulting issuance and delivery of common shares, if any, under the 2012-2014 and 2013-2015 LTI programs will occur in 2015 and 2016, respectively. The vesting of performance shares and resulting issuance and delivery of common shares, if any, under the 2014-2016 LTI program will occur in 2017. Holders of performance shares do not receive voting rights through the ownership of such shares.
	See Note 9 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information with respect to the Equity Incentive Plan and the detailed vesting requirements for the different types of equity awards described above.
	Non-cash Compensation Expense. Compensation expense relating to all awards under the Equity Incentive Plan are included in Selling, administrative, research and development, and general. Non-cash compensation expense by type of award under LTI Programs were as follows, for each period presented:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Service-based non-vested common shares and restricted stock units	$	1.2		$	0.8		$	2.3			$	2.5
	Performance shares	0.5			1.1			1				2
	Market-based shares	0.6			—			1				—
	Total non-cash compensation expense	$	2.3		$	1.9		$	4.3			$	4.5
	The following table presents the allocation of the charges detailed above, by segment:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Fabricated Products	$	1.1		$	0.6		$	2.1			$	1.2
	All Other	1.2			1.3			2.2				3.3
	Total non-cash compensation expense	$	2.3		$	1.9		$	4.3			$	4.5
	Unrecognized Gross Compensation Cost Data. The following table presents unrecognized gross compensation cost data as of June 30, 2014:
		Unrecognized gross compensation costs, by award type			Expected period (in years) over which the remaining gross compensation costs will be recognized, by award type
	Service-based non-vested common shares and restricted stock units	$	9.5		2.9
	Performance shares	$	3		1.5
	Market-based shares	$	5.7		2.6
	Summary of Activity. A summary of the activity with respect to non-vested common shares, restricted stock units and performance shares for the six months ended June 30, 2014 is as follows:
		Non-Vested					Restricted							Performance				Performance Shares (Market-Based)
		Common Shares					Stock Units							Shares
		Shares		Weighted-Average			Units			Weighted-Average				Shares		Weighted-Average		Shares		Weighted-Average
				Grant-Date Fair						Grant-Date Fair						Grant-Date Fair				Grant-Date Fair
				Value per Share						Value per Unit						Value per Share				Value per Share
	Outstanding at December 31, 2013	143,967		$	51.09		5,472			$	51.03			562,554		$	49.26	—		—
	Granted	118,638		66.31			2,235			67.42				—		—		160,868		83.18
	Vested	(62,659	)	52.43			(2,350	)		46.83				(42,545	)	47.04		—		—
	Forfeited	(526	)	55.03			—			—				(1,682	)	50.4		(235	)	83.18
	Canceled	—		—			—			—				(139,384	)	46.77		—		—
	Outstanding at June 30, 2014	199,420		$	59.71		5,357			$	59.71			378,943		$	50.43	160,633		83.18
	A summary of select activity with respect to non-vested common shares, restricted stock units and performance shares for the six months ended June 30, 2013 is as follows:
		Non-Vested					Restricted							Performance
		Common Shares					Stock Units							Shares
		Shares		Weighted-Average			Units			Weighted-Average				Shares		Weighted-Average
				Grant-Date Fair						Grant-Date Fair						Grant-Date Fair
				Value per Share						Value per Unit						Value per Share
	Granted	74,236		$	58.49		2,600			$	57.7			170,298		$	57.57
	Vested	(81,161	)	$	41.67		(2,311	)		$	42.74			(32,312	)	$	34.13
	Stock Options. The Company has fully-vested stock options from a one-time issuance in 2007. As of both June 30, 2014 and December 31, 2013, 20,791 fully-vested options were outstanding, in each case exercisable to purchase common shares at $80.01 per share and having a remaining contractual life of 2.75 and 3.25 years, respectively. The average fair value of the options granted was $39.90. No new options were granted and no existing options were forfeited or exercised during the six months ended June 30, 2014.
Vested Stock. From time to time, the Company issues common shares to non-employee directors electing to receive common shares in lieu of all or a portion of their annual retainer fees. The fair value of these common shares is based on the fair value of the shares at the date of issuance and is immediately recognized in earnings as a period expense. For each six months period ended June 30, 2014 and June 30, 2013, the Company recorded $0.2 relating to common shares granted to non-employee directors in lieu of all or a portion of their annual retainer fees.
Under the Equity Incentive Plan, participants may elect to have the Company withhold common shares to satisfy minimum statutory tax withholding obligations arising in connection with the exercise of stock options and vesting of non-vested shares, restricted stock units and performance shares. Any such shares withheld are canceled by the Company on the applicable vesting dates or earlier dates when service requirements are satisfied, which correspond to the times at which income to the employee is recognized. When the Company withholds these common shares, the Company is required to remit to the appropriate taxing authorities the fair value of the shares withheld as of the vesting date. During the six months ended June 30, 2014 and June 30, 2013, 33,006 and 36,221 common shares, respectively, were withheld and canceled for this purpose. The withholding of common shares by us could be deemed a purchase of the common shares.

Commitments_and_Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Commitments. The Company has a variety of financial commitments, including purchase agreements, forward foreign exchange and forward sales contracts, indebtedness (and related Call Options and Warrants) and letters of credit (see Note 3 and Note 8).
	Refer to Note 10 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for information relating to minimum rental commitments under operating leases and purchase obligations. There were no material changes to such scheduled rental commitments and purchase obligations as of June 30, 2014.
	Environmental Contingencies. The Company is subject to a number of environmental laws and regulations, to potential fines or penalties assessed for alleged breaches of the environmental laws and regulations, and to potential claims based upon such laws and regulations.
	The Company has established procedures for regularly evaluating environmental loss contingencies. The Company’s environmental accruals represent the Company’s undiscounted estimate of costs reasonably expected to be incurred based on presently enacted laws and regulations, existing requirements, currently available facts, existing technology, and the Company’s assessment of the likely remediation actions to be taken.
	In 2012, the Company submitted a final feasibility study to the Washington State Department of Ecology (“Washington State Ecology”) that included recommendations for remediation alternatives primarily to address the historical use of oils containing polychlorinated biphenyls, ("PCBs") at the Company’s Spokane (Trentwood), Washington facility. The Company also signed an amended work order in 2012 with Washington State Ecology allowing certain remediation activities to begin the initiation of a treatability study in regards to proposed PCB remediation methods. The Company began implementation of certain approved sections of the work plan during the third quarter of 2013 and continues to work with Washington State Ecology in developing the implementation work plans, which are subject to Washington State Ecology approval.
	During 2013, at the request of the Ohio Environmental Protection Agency (the “OEPA”), the Company initiated an investigational study of its Newark, Ohio facility related to historical on-site waste disposal. As this work continues and progresses to a risk assessment and feasibility study, the Company will establish and update estimates for probable and estimable remediations, if any. The actual and final cost for remediation will not be fully determinable until a final feasibility study is submitted and accepted by the OEPA and work plans are prepared, which is expected to occur in the next 18 to 24 months.
	At June 30, 2014, the Company’s environmental accrual of $22.2 represented the Company’s estimate of the incremental remediation cost based on proposed alternatives in the final feasibility study related to the Company’s Spokane (Trentwood), Washington facility and currently available facts with respect to its Newark, Ohio facility and certain other locations owned or formally owned by the Company. In accordance with approved and proposed remediation action plans, the Company expects that the implementation and ongoing monitoring could occur over a period of 30 or more years.
	As additional facts are developed, feasibility studies are completed, draft remediation plans are modified, necessary regulatory approvals for the implementation of remediation are obtained, alternative technologies are developed, and/or other factors change, there may be revisions to management’s estimates, and actual costs may exceed the current environmental accruals. The Company believes at this time that it is reasonably possible that undiscounted costs associated with these environmental matters may exceed current accruals by amounts that could be, in the aggregate, up to an estimated $24.9 over the remediation period. It is reasonably possible that the Company’s recorded estimate may change in the next 12 months. Refer to Note 10 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for information relating to environmental contingencies.
	Other Contingencies. The Company is party to various lawsuits, claims, investigations, and administrative proceedings that arise in connection with past and current operations. The Company evaluates such matters on a case-by-case basis, and its policy is to vigorously contest any such claims it believes are without merit. The Company accrues for a legal liability when it is both probable that a liability has been incurred and the amount of the loss is reasonably estimable. Quarterly, in addition to when changes in facts and circumstances require it, the Company reviews and adjusts these accruals to reflect the impacts of negotiations, settlements, rulings, advice of legal counsel and other information, and events pertaining to a particular case. While uncertainties are inherent in the final outcome of such matters and it is presently impossible to determine the actual cost that may ultimately be incurred, management believes that it has sufficiently accrued for such matters and that the ultimate resolution of pending matters will not have a material impact on the Company’s consolidated financial position, operating results, or liquidity.

Derivative_Financial_Instrumen

Derivative Financial Instruments and Related Hedging Programs	6 Months Ended
	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments and Related Hedging Programs	'
	Derivative Financial Instruments and Related Hedging Programs
	Overview. In conducting its business, the Company enters into derivative transactions, including forward contracts and options, to limit its economic (i.e., cash) exposure resulting from (i) metal price risk related to its sale of fabricated aluminum products and the purchase of metal used as raw material for its fabrication operations, (ii) energy price risk relating to fluctuating prices of natural gas and electricity used in its production processes, and (iii) foreign currency requirements with respect to its foreign subsidiaries and cash commitments for equipment purchases denominated in foreign currency. Additionally, in connection with the issuance of the Convertible Notes, the Company purchased cash-settled Call Options relating to the Company’s common stock to limit its exposure to the cash conversion feature of the Convertible Notes (see Note 3).
	The Company’s derivative activities are overseen by the Hedging Committee, which is composed of the chief executive officer, the chief financial officer, the chief accounting officer, the vice president of metal risk and other officers and employees that the chief executive officer selects. The Hedging Committee meets regularly to review derivative positions and strategy and reports to the Company’s Board of Directors on the scope of its activities.
	Hedges of Operational Risks. The Company’s pricing of fabricated aluminum products is generally intended to lock in a conversion margin (representing the value added from the fabrication process(es)) and to pass metal price fluctuations through to its customers. However, in certain instances the Company enters into firm-price arrangements with its customers for stipulated volumes to be delivered in the future. Because the Company generally purchases primary and secondary aluminum on a floating price basis, the volume that it has committed to sell to its customers under a firm-price arrangement creates metal price risks for the Company. The Company uses third-party hedging instruments to limit exposure to metal price risks related to firm-price customer sales contracts. See Note 9 for additional information regarding the Company’s material derivative positions relating to hedges of operational risks, and their respective fair values.
	A majority of the Company’s derivative contracts relating to hedges of operational risks contain credit risk-related contingency features that could require the Company to provide additional collateral in the event the Company’s credit rating were to be downgraded. To minimize the exposure to additional collateral requirements related to its liability hedge positions, the Company allocates hedging transactions among its counterparties, uses options as part of its hedging activities, or both. The aggregate fair value of the Company’s derivative instruments that contain credit risk-related contingency features and were in a net liability position at June 30, 2014 and December 31, 2013 was $0.2 and $1.6, respectively.
	The Company regularly reviews the creditworthiness of its derivative counterparties and does not expect to incur significant loss from the failure of any counterparties to perform under any agreements.
	During the six months ended June 30, 2014 and June 30, 2013, total fabricated products shipments that contained firm-price terms were (in millions of pounds) 68.5 and 58.2, respectively. At June 30, 2014, the Fabricated Products segment held contracts for the delivery of fabricated aluminum products that had the effect of creating price risk on anticipated purchases of aluminum for the remainder of 2014, and 2015, totaling approximately (in millions of pounds) 49.3 and 4.3, respectively.
	Hedges Relating to the Convertible Notes. As described in Note 3, the Company issued Convertible Notes in the aggregate principal amount of $175.0 in March 2010. The conversion feature of the Convertible Notes can only be settled in cash and must be bifurcated from the Convertible Notes and treated as a separate derivative instrument for financial reporting purposes. In order to offset the cash flow risk associated with the Bifurcated Conversion Feature, the Company purchased Call Options, which are accounted for as derivative instruments. The Company expects that the realized gain, if any, from the Call Options will substantially offset the realized loss, if any, of the Bifurcated Conversion Feature upon maturity of the Convertible Notes. However, because assumptions used to determine the fair values of the Call Option and the Bifurcated Conversion Feature are not identical, net unrealized mark-to-market gains and losses on the two derivatives are recorded from quarter to quarter. See Note 9 for additional information regarding the fair values of the Call Options and the Bifurcated Conversion Feature.
	Realized and Unrealized Gains and Losses. Realized and unrealized gains (losses) associated with all derivative contracts consisted of the following, for each period presented:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Realized gains (losses):
	Aluminum	$	1.3		$	(1.6	)	$	2.1		$	(1.6	)
	Natural Gas	0.5			(0.1		)	1.2			(0.8		)
	Electricity	(0.5		)	(0.1		)	—			(0.1		)
	Total realized gains (losses)	$	1.3		$	(1.8	)	$	3.3		$	(2.5	)
	Unrealized gains (losses):
	Aluminum	$	0.6		$	(1.8	)	$	2.3		$	(6.2	)
	Natural Gas	(0.2		)	(1.9		)	0.6			0.8
	Electricity	1.2			(0.6		)	0.7			0.6
	Foreign Currency	(0.1		)	0.1			(0.1		)	(0.1		)
	Call Options relating to the Convertible Notes	2.5			(9.1		)	6.9			(3.1		)
	Bifurcated Conversion Feature of the Convertible Notes	(2.0		)	8.2			(5.5		)	2.6
	Total unrealized gains (losses)	$	2		$	(5.1	)	$	4.9		$	(5.4	)
	The following table summarizes the Company’s material derivative positions at June 30, 2014:
	Aluminum		Maturity Period (month/year)	Notional Amount of contracts (mmlbs)
	Fixed price purchase contracts		7/14 through 12/15	44.1
	Fixed price sales contracts		7/14 through 12/14	1.3
	Midwest premium swap contracts1		7/14 through 12/15	42.3
	Natural Gas2		Maturity Period (month/year)	Notional Amount of contracts (mmbtu)
	Fixed price purchase contracts		7/14 through 12/16	6,150,000
	Electricity		Maturity Period (month/year)	Notional Amount of contracts (Mwh)
	Fixed price purchase contracts		7/14 through 12/15	285,625
	Hedges Relating to the Convertible Notes		Contract Period (month/year)	Notional Amount of contracts (Common Shares)
	Bifurcated Conversion Feature3		3/10 through 3/15	3,649,608
	Call Options3		3/10 through 3/15	3,649,608
	______________________
	1	Regional premiums represent the premium over the London Metal Exchange price for primary aluminum which is incurred on the Company’s purchases of primary aluminum.
	2	As of June 30, 2014, the Company’s exposure to fluctuations in natural gas prices had been substantially reduced for approximately 88%, 82% and 30% of the expected natural gas purchases for the remainder of 2014, 2015 and 2016, respectively.
	3	The Bifurcated Conversion Feature represents the cash conversion feature of the Convertible Notes. The Call Options expire on the maturity or earlier conversion of the Convertible Notes and have an exercise price equal to the conversion price of the Convertible Notes, subject to anti-dilution adjustments substantially similar to the anti-dilution adjustments for the Convertible Notes. Although the fair value of the Call Options is derived from a notional number of shares of the Company’s common stock, the Call Options may only be settled in cash.
	The Company enters into derivative contracts with counterparties, some of which are subject to enforceable master netting arrangements and some of which are not. The Company reflects the fair value of its derivative contracts on a gross basis on the Consolidated Balance Sheets (see Note 2).
	The following tables present offsetting information regarding the Company’s derivatives by type of counterparty as of June 30, 2014:
	Derivative Assets and Collateral Held by Counterparty
											Gross Amounts Not Offset in the Consolidated Balance Sheets
		Gross Amounts of Recognized Assets			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Assets Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Received		Net Amount
	Counterparty (with Netting Agreements)	$	2		$	—		$	2		$	0.8		$	—	$	1.2
	Counterparty (without Netting Agreements)1	87.6			—			87.6			—			—		87.6
	Counterparty (with partial Netting Agreements)	1			—			1			0.3			—		0.7
	Total	$	90.6		$	—		$	90.6		$	1.1		$	—	$	89.5
	Derivative Liabilities and Collateral Held by Counterparty
											Gross Amounts Not Offset in the Consolidated Balance Sheets
		Gross Amounts of Recognized Liabilities			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Liabilities Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Pledged		Net Amount
	Counterparty (with Netting Agreements)	$	(0.8	)	$	—		$	(0.8	)	$	(0.8	)	$	—	$	—
	Counterparty (without Netting Agreements)1	(88.7		)	—			(88.7		)	—			—		(88.7		)
	Counterparty (with partial Netting Agreements)	(0.5		)	—			(0.5		)	(0.3		)	—		(0.2		)
	Total	$	(90.0	)	$	—		$	(90.0	)	$	(1.1	)	$	—	$	(88.9	)
	_________________
	1	Such amounts include the fair value of the Bifurcated Conversion Feature and Call Options at June 30, 2014 (see Note 9).
	The following tables present offsetting information regarding the Company’s derivatives by type of counterparty as of December 31, 2013:
	Derivative Assets and Collateral Held by Counterparty
											Gross Amounts Not Offset in the Consolidated Balance Sheets
		Gross Amounts of Recognized Assets			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Assets Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Received		Net Amount
Counterparty (with Netting Agreements)	$	1		$	—		$	1		$	0.8		$	—	$	0.2
Counterparty (without Netting Agreements)1	80.4			—			80.4			—			—		80.4
Counterparty (with partial Netting Agreements)	0.4			—			0.4			0.4			—		—
Total	$	81.8		$	—		$	81.8		$	1.2		$	—	$	80.6
Derivative Liabilities and Collateral Held by Counterparty
										Gross Amounts Not Offset in the Consolidated Balance Sheets
	Gross Amounts of Recognized Liabilities			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Liabilities Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Pledged		Net Amount
Counterparty (with Netting Agreements)	$	(1.6	)	$	—		$	(1.6	)	$	(0.8	)	$	—	$	(0.8	)
Counterparty (without Netting Agreements)1	(83.2		)	—			(83.2		)	—			—		(83.2		)
Counterparty (with partial Netting Agreements)	(1.3		)	—			(1.3		)	(0.4		)	—		(0.9		)
Total	$	(86.1	)	$	—		$	(86.1	)	$	(1.2	)	$	—	$	(84.9	)
_________________
1	Such amounts include the fair value of the Bifurcated Conversion Feature and Call Options at December 31, 2013 (see Note 9).

Fair_Value_Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurement	'
	Fair Value Measurements
	Overview
	The Company applies the fair value hierarchy established by GAAP for the recognition and measurement of assets and liabilities. An asset or liability’s fair value classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. In determining fair value, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible, and considers counterparty risk in its assessment of fair value.
	The fair values of financial assets and liabilities are evaluated and measured on a recurring basis. As part of that evaluation process, the Company reviews the underlying inputs that are significant to the fair value measurement of financial instruments to determine if a transfer among hierarchy levels is appropriate. The Company historically has not had significant transfers into or out of each hierarchy level.
	Financial assets and liabilities that the Company measures at fair value as required by GAAP include: (i) its derivative instruments; (ii) the plan assets of the VEBAs and the Company’s Canadian defined benefit pension plan measured annually at December 31; and (iii) available for sale securities, consisting of debt investment securities and investments related to the Company’s deferred compensation plan (see Note 5). The Company records certain other financial assets and liabilities at carrying value (see the tables below for the fair value disclosure of those assets and liabilities).
	The majority of the Company’s non-financial assets and liabilities, which include goodwill, intangible assets, inventories and property, plant, and equipment, are not required to be measured at fair value on a recurring basis. However, if certain triggering events occur (or at least annually for goodwill), an evaluation of a non-financial asset or liability is required, potentially resulting in an adjustment to the carrying amount of such asset or liability. For the quarter and six months ended June 30, 2014 and June 30, 2013, the Company concluded that none of its non-financial assets and liabilities subject to fair value assessments on a non-recurring basis required a material adjustment to the carrying amount of such assets and liabilities.
	Fair Values of Financial Assets and Liabilities
	Fair Values of Derivative Assets and Liabilities. The Company’s derivative contracts are valued at fair value using significant observable and unobservable inputs.
	Commodity, Energy and Foreign Currency Derivatives - The fair values of a majority of these derivative contracts are based upon trades in liquid markets. Valuation model inputs can generally be verified, and valuation techniques do not involve significant judgment. The fair values of such financial instruments are generally classified within Level 2 of the fair value hierarchy. The Company, however, has some derivative contracts that do not have observable market quotes. For these financial instruments, management uses significant unobservable inputs (e.g., information concerning regional premiums for swaps). Where appropriate, valuations are adjusted for various factors, such as bid/offer spreads. The fair value of these financial instruments are classified as Level 3 in the fair value hierarchy.
	Bifurcated Conversion Feature and Call Options - The fair value of the Bifurcated Conversion Feature is measured as the difference in the estimated fair value of the Convertible Notes and the estimated fair value of the Convertible Notes without the cash conversion feature. The Convertible Notes are valued based on the trading price of the Convertible Notes each period-end (see “All Other Financial Assets and Liabilities” below). The fair value of the Convertible Notes without the cash conversion feature is the present value of the series of the remaining fixed income cash flows under the Convertible Notes, with a maturity of April 1, 2015. During the second quarter of 2014, the Bifurcated Conversion Feature and Call Options were reclassified as current liabilities and assets, respectively, and were included in the Consolidated Balance Sheet as a portion of Other accrued liabilities and Prepaid expenses and other current assets, respectively, as of June 30, 2014.
	The Company determines the fair value of the Call Options using a binomial lattice valuation model. The inputs to the model at June 30, 2014 were as follows:
	The Company’s stock price at June 30, 2014	$	72.87
	Quarterly dividend yield (per share) upon purchase of the Call Option1	$	0.24
	Risk-free interest rate2	0.08		%
	Credit spread (basis points)3	130
	Expected volatility rate4	17		%
	______________________
	1	The quarterly dividend in the second quarter of 2014 was $0.35 per share, but the model assumes a $0.24 per share quarterly dividend as was paid at the inception of the Call Options. Quarterly dividends in excess of $0.24 per share do not affect the Call Options’ value due to anti-dilution adjustments.
	2	The risk-free rate was based on the six-month Constant Maturity Treasury rate and one-year Constant Maturity Treasury rate on June 30, 2014.
	3	The credit spread is based on the Company’s long-term credit rating of BB issued by Standard & Poor’s.
	4	The volatility rate was based on both observed volatility, which is based on the Company’s historical stock price, and implied volatility from the Company’s traded options. Such volatility was further adjusted to take into consideration market participant risk tolerance.
	The aggregate fair value of our derivatives, recorded on the Consolidated Balance Sheets at June 30, 2014 and December 31, 2013, was a net asset of $0.6 and a net liability of $4.3, respectively. The increase in net position from liability to asset during the six months ended June 30, 2014 was primarily due to changes in the underlying commodity and energy prices during such period. Changes in the fair value of our derivative contracts relating to operational hedging activities are reflected in operating income. Such changes in the fair value of these contracts resulted in the recognition of a $3.5 unrealized mark-to-market gain during the six months ended June 30, 2014.
	VEBA and Canadian Pension Plan Assets. The fair value of the plan assets of the VEBAs and the Company’s Canadian pension plan is measured annually on December 31. In determining the fair value of the plan assets at each annual period end, the Company utilizes primarily the results of valuations supplied by the investment advisors responsible for managing the assets of each plan. See Note 12 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information with respect to the fair value of the plan assets of the VEBAs and the Company’s Canadian pension plan.
	Available for sale securities. The Company holds debt investment securities. The fair value of the debt investment securities, which consist of commercial paper and corporate bonds, is determined based on valuation models that use observable market data. At June 30, 2014, the remaining maturity period with respect to short-term investments ranged from 32 days to approximately nine months. In addition to debt investment securities, the Company also holds assets in various investment funds at certain registered investment companies in connection with its deferred compensation program (see Note 5). Such assets are accounted for as available for sale securities and are measured and recorded at fair value based on the net asset value of the investment funds on a recurring basis. The fair value input of the available for sale securities is considered either a Level 1 or Level 2 input depending on whether the debt security or investment fund is traded on a public exchange. The amortized cost for available for sale securities approximates their fair value.
	All Other Financial Assets and Liabilities. The Company believes that the fair value of its cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate their respective carrying values due to their short maturities and nominal credit risk.
	The fair value of the Convertible Notes and Senior Notes is based on their trading prices and is considered a Level 1 input in the fair value hierarchy (see Note 3 for the carrying values of the Convertible Notes and the Senior Notes).
	The following table presents the Company’s financial instruments, classified under the appropriate level of the fair value hierarchy, as of June 30, 2014:
		Level 1			Level 2			Level 3		Total
	FINANCIAL ASSETS:
	Derivative Instruments:
	Aluminum -
	Fixed price purchase contracts	$	—		$	0.8		$	—	$	0.8
	Midwest premium swap contracts	—			—			1.4		1.4
	Natural Gas -
	Fixed price purchase contracts	—			0.9			—		0.9
	Electricity -
	Fixed price purchase contracts	—			1			—		1
	Hedges Relating to the Convertible Notes -
	Call Options	—			86.5			—		86.5
	All Other Financial Assets:
	Cash and cash equivalents	69.7			104.5			—		174.2
	Short-term investments	—			127.2			—		127.2
	Deferred compensation plan asset	—			7.4			—		7.4
	Total assets	$	69.7		$	328.3		$	1.4	$	399.4
	FINANCIAL LIABILITIES:
	Derivative Instruments:
	Aluminum -
	Fixed price purchase contracts	$	—		$	(0.5	)	$	—	$	(0.5	)
	Natural Gas -
	Fixed price purchase contracts	—			(0.6		)	—		(0.6		)
	Electricity -
	Fixed price purchase contracts	—			(0.2		)	—		(0.2		)
	Hedges Relating to the Convertible Notes -
	Bifurcated Conversion Feature	—			(88.7		)	—		(88.7		)
	All Other Financial Liabilities:
	Senior Notes	(253.2		)	—			—		(253.2		)
	Convertible Notes	(269.7		)	—			—		(269.7		)
	Total liabilities	$	(522.9	)	$	(90.0	)	$	—	$	(612.9	)
	The following table presents the Company’s financial instruments, classified under the appropriate level of the fair value hierarchy, as of December 31, 2013:
		Level 1			Level 2			Level 3		Total
	FINANCIAL ASSETS:
	Derivative Instruments:
	Aluminum -
Fixed price purchase contracts	$	—		$	0.1		$	—	$	0.1
Midwest premium swap contracts	—			—			1.1		1.1
Natural Gas -
Fixed price purchase contracts	—			0.5			—		0.5
Electricity -
Fixed price purchase contracts	—			0.5			—		0.5
Foreign Currency -
Euro	—			0.1			—		0.1
Hedges Relating to the Convertible Notes -
Call Options	—			79.5			—		79.5
All Other Financial Assets:
Cash and cash equivalents	57.7			111.8			—		169.5
Short-term investments	—			129.5			—		129.5
Deferred compensation plan asset	—			6.5			—		6.5
Total assets	$	57.7		$	328.5		$	1.1	$	387.3
FINANCIAL LIABILITIES:
Derivative Instruments:
Aluminum -
Fixed price purchase contracts	$	—		$	(1.8	)	$	—	$	(1.8	)
Natural Gas -
Fixed price purchase contracts	—			(0.8		)	—		(0.8		)
Electricity -
Fixed price purchase contracts	—			(0.4		)	—		(0.4		)
Hedges Relating to the Convertible Notes -
Bifurcated Conversion Feature	—			(83.1		)	—		(83.1		)
All Other Financial Liabilities:
Senior Notes	(255.4		)	—			—		(255.4		)
Convertible Notes	(260.0		)	—			—		(260.0		)
Total liabilities	$	(515.4	)	$	(86.1	)	$	—	$	(601.5	)
Financial instruments classified as Level 3 in the fair value hierarchy represent Midwest premium swap contracts for which at least one significant unobservable input in the valuation model is a management estimate. This is necessary due to the lack of an exchange traded product with observable market pricing data. To estimate fair value, the Company uses a forward curve that represents the mid-point of the bid-ask spread based on trade activity and market information obtained through discussions with a variety of counterparties including traders, banks and producers.
The following table presents a reconciliation of activity for the Midwest premium derivative contracts on a net basis:
	Level 3
Balance at December 31, 2013	$	1.1
Total realized/unrealized gains included in:
Cost of goods sold excluding depreciation and amortization and other items and Unrealized (gains) losses on derivative instruments	4.1
Transactions involving Level 3 derivative contracts:
Purchases	0.6
Sales	—
Issuances	—
Settlements	(4.4		)
Transactions involving Level 3 derivatives — net	(3.8		)
Transfers in and (or) out of Level 3 valuation hierarchy	—
Balance at June 30, 2014	$	1.4
Total gains included in Unrealized (gains) losses on derivative instruments, attributable to the change in unrealized gains/losses relating to derivative contracts held at June 30, 2014:	$	1.1
Fair Values of Non-financial Assets and Liabilities
See Note 12 of Notes to Consolidated Financial Statements included in Part II, Item 8. “Financial Statements and Supplementary Data” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013 for additional information with respect to the fair value of the Company’s non-financial assets and liabilities.

Earnings_Per_Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	Earnings Per Share
	Basic and diluted earnings per share were calculated as follows, for each period presented:
		Quarter Ended				Six Months Ended
		June 30,				June 30,
		2014		2013		2014		2013
	Numerator:
	Net income	$	24.5	$	18.6	$	40.3	$	52.1
	Denominator — Weighted-average common shares outstanding (in thousands):
	Basic1	17,841		18,742		17,889		19,027
	Add: dilutive effect of non-vested common shares, restricted stock units and performance shares	112		112		133		135
	Add: dilutive effect of warrants	505		91		490		94
	Diluted2	18,458		18,945		18,512		19,256
	Earnings per common share, Basic:
	Net income per share	$	1.38	$	0.99	$	2.25	$	2.73
	Earnings per common share, Diluted:
	Net income per share	$	1.33	$	0.98	$	2.18	$	2.7
	______________________
	1	The basic weighted-average number of common shares outstanding during the period excludes non-vested common shares, restricted stock units, performance shares and market-based shares.
	2	The diluted weighted-average number of common shares outstanding during the periods were calculated using the treasury method.
	Options to purchase 20,791 common shares at an average exercise price of $80.01 per share were outstanding at both June 30, 2014 and December 31, 2013. The number of potentially dilutive stock options were excluded from the computation of diluted net income per share as their effect would have been anti-dilutive for each of the periods presented.
	Warrants relating to approximately 3.6 million common shares were outstanding at both June 30, 2014 (at which date the average exercise price was approximately $60.89 per share) and June 30, 2013 (at which date the average exercise price was approximately $61.19 per share).
	During the six months ended June 30, 2014 and June 30, 2013, the Company paid approximately $12.8 ($0.70 per common share) and $11.6 ($0.60 per common share), respectively, in cash dividends to stockholders, including the holders of non-vested common shares, and dividend equivalents to the holders of certain restricted stock units and to the holders of performance shares with respect to approximately one-half of the performance shares.
	From time to time, the Company repurchases shares pursuant to a stock repurchase program authorized by the Company’s Board of Directors. Repurchase transactions will occur at such times and prices as management deems appropriate and will be funded with the Company’s excess liquidity after giving consideration to internal and external growth opportunities and future cash flows. Repurchases may be in open-market transactions or in privately negotiated transactions, and the program may be modified or terminated by the Company’s Board of Directors at any time.
	During the six months ended June 30, 2014 and June 30, 2013, the Company repurchased 346,781 shares of common stock (at a weighted-average price of $69.25 per share) and 654,277 shares of common stock (at a weighted-average price of $61.95 per share), respectively, pursuant to the stock repurchase program. The total cost of $24.0 and $40.5 was recorded as Treasury Stock at June 30, 2014 and June 30, 2013, respectively. At June 30, 2014 and December 31, 2013, $93.6 and $117.6, respectively, were available to repurchase the Company’s common shares pursuant to the stock repurchase program.

Segment_Information

Segment Information	6 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
Segment and Geographical Area Information	'
	Segment Information
	The Company’s primary line of business is 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 (“Aero/HS”), general engineering (“GE”), automotive, and other industrial end market applications. The Company operates 11 focused production facilities in the United States and one in Canada. Consistent with the manner in which the Company’s chief operating decision maker reviews and evaluates the Company’s business, the Fabricated Products business is treated as a single operating segment.
	In addition to the Fabricated Products segment, the Company has a business unit called All Other, which provides general and administrative support for the Company's operations. For purposes of segment reporting under GAAP, the Company treats the Fabricated Products segment as a reportable segment. All Other is not considered a reportable segment.
	The accounting policies of the Fabricated Products segment are the same as those described in Note 1. Segment results are evaluated internally by management before any allocation of corporate overhead and without any charge for income taxes, interest expense, or other operating charges, net.
	The following tables provide financial information by reporting segment for each period or as of each period-end, as applicable.
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Net sales:
	Fabricated Products	$	344.1		$	328.9		$	679.2		$	666.3
	Segment operating income (loss):
	Fabricated Products 1,2	$	50.2		$	45		$	85.6		$	100.2
	All Other3	(3.8		)	(4.9		)	(7.1		)	(10.1		)
	Total operating income	$	46.4		$	40.1		$	78.5		$	90.1
	Interest expense	(9.2		)	(9.0		)	(18.0		)	(18.3		)
	Other income, net	1.8			(0.8		)	3.7			0.2
	Income before income taxes	$	39		$	30.3		$	64.2		$	72
	Depreciation and amortization:
	Fabricated Products	$	7.7		$	6.9		$	14.9		$	13.8
	All Other	—			0.1			0.2			0.2
	Total depreciation and amortization	$	7.7		$	7		$	15.1		$	14
	Capital expenditures:
	Fabricated Products	$	14.2		$	16.5		$	29.5		$	25.4
	All Other	0.5			0.2			0.6			0.6
	Total capital expenditures	$	14.7		$	16.7		$	30.1		$	26
	Income taxes paid:
	Fabricated Products —
	United States	$	0.1		$	0.3		$	0.2		$	0.6
	Canada	0.3			0.3			0.9			0.7
	Total income taxes paid	$	0.4		$	0.6		$	1.1		$	1.3
	______________________
	1.	Operating results in the Fabricated Products segment for the quarter ended June 30, 2014 included a charge of $0.6 as a result of decrementing a prior year, higher cost LIFO layer. Operating results in the Fabricated Products segment for the six months ended June 30, 2014 included a charge of $2.4 as a result of decrementing a prior year, higher cost layer.
	2.	Fabricated Products segment operating income included non-cash mark-to-market gains (losses) on primary aluminum, natural gas, electricity and foreign currency hedging activities totaling $1.5 and $(4.2) for the quarters ended June 30, 2014 and June 30, 2013, respectively. Non-cash mark-to-market gains (losses) on primary aluminum, natural gas, electricity and foreign currency hedging activities totaled $3.5 and $(4.9) for the six months ended June 30, 2014 and June 30, 2013, respectively. For further discussion regarding mark-to-market matters, see Note 8.
	3.	Operating loss in All Other included VEBA net periodic pension benefit income of $6.1 and $5.7 for the quarters ended June 30, 2014 and June 30, 2013, respectively. VEBA net periodic pension benefit income was $11.7 and $11.3 for the six months ended June 30, 2014 and June 30, 2013, respectively.
		June 30, 2014			December 31, 2013
	Assets:
	Fabricated Products	$	851.4		$	852.5
	All Other1	921.2			918.4
	Total assets	$	1,772.60		$	1,770.90
	_____________________
	1.	Assets in All Other represent primarily all of the Company’s cash and cash equivalents, short-term investments, financial derivative assets, net assets in respect of VEBA(s) (see Note 5) and net deferred income tax assets.
	Net sales by product categories, which are based on end market applications, for the Fabricated Products segment are as follows:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Net sales:
	Aero/HS products	$	173		$	165.1		$	336.6		$	344.7
	GE products	107.3			110.2			219.5			216
	Automotive Extrusions	44.7			31			85.5			61.8
	Other products	19.1			22.6			37.6			43.8
	Total net sales	$	344.1		$	328.9		$	679.2		$	666.3

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	6 Months Ended
	Jun. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Cash Flow Information	'
	Supplemental Cash Flow Information
		Six Months Ended
		June 30,
		2014		2013
	Supplemental disclosure of cash flow information:
	Interest paid	$	12.1	$	14
	Income taxes paid	$	1.1	$	1.3
	Supplemental disclosure of non-cash transactions:
	Stock repurchases not yet settled (accrued in accounts payable)	$	0.3	$	0.6
	Non-cash capital expenditures	$	1.1	$	4.4
	Capital leases acquired	$	—	$	0.2

Other_Income_Expense_Net

Other Income (Expense), Net	6 Months Ended
	Jun. 30, 2014
Other Income and Expenses [Abstract]	'
Other Income (Expense), Net	'
	Other Income (Expense), Net
	Other income (expense), net consisted of the following, for each period presented:
		Quarter Ended					Six Months Ended
		June 30,					June 30,
		2014		2013			2014		2013
	Interest income	$	0.2	$	—		$	0.5	$	0.1
	Unrealized gains (losses) on financial derivatives1	0.5		(0.9		)	1.4		(0.5		)
	Realized gains on investments	0.2		0.3			0.4		0.8
	All other, net	0.9		(0.2		)	1.4		(0.2		)
	Other non-operating income (expense), net	$	1.8	$	(0.8	)	$	3.7	$	0.2
	______________________
	1	See “Hedges Relating to the Convertible Notes” in Note 8 for discussion of such instruments.

Other_Comprehensive_Income

Other Comprehensive Income	6 Months Ended
	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]	'
Other Comprehensive Income Disclosure	'
	Other Comprehensive Income
	The following table presents the tax effect allocated to each component of Other comprehensive income for each period presented:
		Before-Tax			Income Tax			Net-of-Tax
		Amount			(Expense) Benefit3			Amount
	Quarter Ended June 30, 2014
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial gain1	$	(0.6	)	$	0.2		$	(0.4	)
	Amortization of prior service cost1	2.6			(1.0		)	1.6
	Other comprehensive income relating to VEBAs	2			(0.8		)	1.2
	Available for sale securities:
	Unrealized gains on available for sale securities	0.2			(0.1		)	0.1
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.1		)	0.1			—
	Other comprehensive income relating to available for sale securities	0.1			—			0.1
	Foreign currency translation adjustment	(0.1		)	—			(0.1		)
	Cumulative tax rate adjustment	—			0.9			0.9
	Other comprehensive income	$	2		$	0.1		$	2.1
	Quarter Ended June 30, 2013
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial loss1	$	0.4		$	(0.1	)	$	0.3
	Amortization of prior service cost1	1			(0.4		)	0.6
	Other comprehensive income relating to VEBAs	1.4			(0.5		)	0.9
	Available for sale securities:
	Unrealized gains on available for sale securities	0.2			(0.1		)	0.1
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.2		)	0.1			(0.1		)
	Other comprehensive income relating to available for sale securities	—			—			—
	Foreign currency translation adjustment	0.4			—			0.4
	Other comprehensive income	$	1.8		$	(0.5	)	$	1.3
	Six Months Ended June 30, 2014
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial gain1	$	(0.9	)	$	0.3		$	(0.6	)
	Amortization of prior service cost1	5.4			(2.0		)	3.4
	Other comprehensive income relating to VEBAs	4.5			(1.7		)	2.8
	Available for sale securities:
	Unrealized gains on available for sale securities	0.3			(0.1		)	0.2
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.2		)	0.1			(0.1		)
	Other comprehensive income relating to available for sale securities	0.1			—			0.1
	Foreign currency translation adjustment	0.1			—			0.1
	Other comprehensive income	$	4.7		$	(1.7	)	$	3
	Six Months Ended June 30, 2013
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial loss1	$	0.7		$	(0.2	)	$	0.5
	Amortization of prior service cost1	2.1			(0.8		)	1.3
	Other comprehensive income relating to VEBAs	2.8			(1.0		)	1.8
	Available for sale securities:
	Unrealized gains on available for sale securities	0.5			(0.2		)	0.3
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.6		)	0.2			(0.4		)
	Other comprehensive income relating to available for sale securities	(0.1		)	—			(0.1		)
	Foreign currency translation adjustment	0.8			—			0.8
	Other comprehensive income	$	3.5		$	(1.0	)	$	2.5
	________________
	1	Amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments were included as a component of Net periodic pension benefit income relating to VEBAs.
	2	Amounts reclassified out of Accumulated other comprehensive income relating to sales of available for sale securities were included as a component of Other income (expense), net. The Company uses the specific identification method to determine the amount reclassified out of accumulated other comprehensive income.
	3	Income tax amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments and sales of available for sale securities were included as a component of Income tax provision.

Guarantor_and_NonGuarantor_Fin

Guarantor and Non-Guarantor Financial Statements (Notes)	6 Months Ended
	Jun. 30, 2014
Guarantor and Non-Guarantor Financial Statement [Abstract]	'
Guarantor and Non-Guarantor Financial Statements	'
	Condensed Guarantor and Non-Guarantor Financial Information
	The Company issued $225.0 aggregate principal amount of its Senior Notes pursuant to an indenture dated May 23, 2012(the “Indenture”), among Kaiser Aluminum Corporation (the “Parent”), the subsidiary guarantors party thereto (the “Guarantor Subsidiaries”) and Wells Fargo Bank, National Association, as trustee (the “Trustee”). The Guarantor Subsidiaries currently include Kaiser Aluminum Investments Company, Kaiser Aluminum Fabricated Products, LLC, Kaiser Aluminum Mill Products Inc., Kaiser Aluminum Washington, LLC and Kaiser Aluminum Alexco, LLC, all of which are 100% owned by the Parent. The guarantees are full and unconditional and joint and several but have customary releases in the following situations: i) the sale of the Guarantor Subsidiary or all of its assets; ii) the declaration of a Guarantor Subsidiary as an unrestricted subsidiary under the Indenture; iii) the termination or release of the Guarantor Subsidiary’s guarantee of certain other indebtedness; or iv) the exercise of legal defeasance or covenant defeasance by the Company or the discharge of the Company’s obligations under the Indenture.
	The following condensed consolidating financial information as of June 30, 2014 and December 31, 2013, and for the quarters and six months ended June 30, 2014 and June 30, 2013 present (i) the financial position, results of operation and cash flows for each of (a) the Parent, (b) the Guarantor Subsidiaries on a combined basis, and (c) the Non-Guarantor Subsidiaries (as defined below) on a combined basis, (ii) the adjustments necessary to eliminate investments in subsidiaries and intercompany balances and transactions among the Parent, the Guarantor Subsidiaries and the Non-Guarantor Subsidiaries, and (iii) the resulting totals, reflecting information for the Company on a consolidated basis, as reported. In the following tables, “Non-Guarantor Subsidiaries” refers to Kaiser Aluminum Canada Limited, Trochus Insurance Company, DCO Management, LLC, Kaiser Aluminum France, S.A.S. and Kaiser Aluminum Beijing Trading Company; and “Consolidating Adjustments” represent the adjustments necessary to eliminate the investments in the Company’s subsidiaries and other intercompany sales and cost of sales transactions. The condensed consolidating financial information should be read in conjunction with the consolidated financial statements herein.
	CONDENSED CONSOLIDATING BALANCE SHEET
	June 30, 2014
		Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	ASSETS
	Current assets:
	Cash and cash equivalents	$	5		$	164.7		$	4.5		$	—		$	174.2
	Short-term investments	—			127.2			—			—			127.2
	Receivables:
	Trade, less allowance for doubtful receivables	—			119			4.1			—			123.1
	Intercompany receivables	—			26.1			0.7			(26.8		)	—
	Other	—			5.1			5.9			—			11
	Inventories	—			193.8			5.1			(0.8		)	198.1
	Prepaid expenses and other current assets	87.5			47.6			0.4			—			135.5
	Total current assets	92.5			683.5			20.7			(27.6		)	769.1
	Investments in and advances to subsidiaries	1,505.40			28.1			—			(1,533.5		)	—
	Property, plant, and equipment — net	—			425.9			15.5			—			441.4
	Long-term intercompany receivables	—			—			16.2			(16.2		)	—
	Net assets of VEBAs	—			422.2			—			—			422.2
	Deferred tax assets — net	—			36.9			—			8.9			45.8
	Intangible assets — net	—			32.9			—			—			32.9
	Goodwill	—			37.2			—			—			37.2
	Other assets	4.9			19			0.1			—			24
	Total	$	1,602.80		$	1,685.70		$	52.5		$	(1,568.4	)	$	1,772.60
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Current liabilities:
	Accounts payable	$	0.6		$	64.2		$	7.3		$	—		$	72.1
	Intercompany payable	23.4			8.5			2			(33.9		)	—
	Accrued salaries, wages, and related expenses	—			30.3			3.5			—			33.8
	Other accrued liabilities	92.2			21.7			1.2			—			115.1
	Current portion of long-term debt	167.9			—			—			—			167.9
	Short-term capital lease	—			0.1			—			—			0.1
	Total current liabilities	284.1			124.8			14			(33.9		)	389
	Deferred tax liability	—			—			1.2			—			1.2
	Long-term intercompany payable	—			16.2			—			(16.2		)	—
	Long-term liabilities	—			52.7			11			—			63.7
	Long-term debt	225			—			—			—			225
	Total liabilities	509.1			193.7			26.2			(50.1		)	678.9
	Total stockholders’ equity	1,093.70			1,492.00			26.3			(1,518.3		)	1,093.70
	Total	$	1,602.80		$	1,685.70		$	52.5		$	(1,568.4	)	$	1,772.60
	CONDENSED CONSOLIDATING BALANCE SHEET
	December 31, 2013
		Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	ASSETS
	Current assets:
	Cash and cash equivalents	$	5		$	157.7		$	6.8		$	—		$	169.5
	Short-term investments	—			129.5			—			—			129.5
	Receivables:
	Trade, less allowance for doubtful receivables	—			117.7			2.1			—			119.8
	Intercompany receivables	—			0.1			0.2			(0.3		)	—
	Other	—			5.3			8.1			—			13.4
	Inventories	—			208.6			6.4			(0.6		)	214.4
	Prepaid expenses and other current assets	0.1			43.7			0.4			—			44.2
	Total current assets	5.1			662.6			24			(0.9		)	690.8
	Investments in and advances to subsidiaries	1,437.90			26.5			—			(1,464.4		)	—
	Property, plant, and equipment — net	—			414			15.3			—			429.3
	Long-term intercompany receivables	31.3			1.6			9.5			(42.4		)	—
	Net assets of VEBAs	—			406			—			—			406
	Deferred tax assets — net	—			60.2			—			8.9			69.1
	Intangible assets — net	—			33.7			—			—			33.7
	Goodwill	—			37.2			—			—			37.2
Other assets	86.2			18.5			0.1			—			104.8
Total	$	1,560.50		$	1,660.30		$	48.9		$	(1,498.8	)	$	1,770.90
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	1.1		$	56.3		$	5.5		$	—		$	62.9
Intercompany payable	—			13.9			0.1			(14.0		)	—
Accrued salaries, wages, and related expenses	—			39.3			3.4			—			42.7
Other accrued liabilities	3.5			39.9			1.4			—			44.8
Short-term capital lease	—			0.2			—			—			0.2
Total current liabilities	4.6			149.6			10.4			(14.0		)	150.6
Deferred tax liability	—			—			1.2			—			1.2
Long-term intercompany payable	—			40.7			1.7			(42.4		)	—
Long-term liabilities	83.2			52			11.2			—			146.4
Long-term debt	388.5			—			—			—			388.5
Total liabilities	476.3			242.3			24.5			(56.4		)	686.7
Total stockholders’ equity	1,084.20			1,418.00			24.4			(1,442.4		)	1,084.20
Total	$	1,560.50		$	1,660.30		$	48.9		$	(1,498.8	)	$	1,770.90
CONDENSED CONSOLIDATING STATEMENT OF COMPREHESIVE INCOME
Quarter Ended June 30, 2014
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	335.7		$	34		$	(25.6	)	$	344.1
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			270.8			29.7			(25.0		)	275.5
Unrealized gains on derivative instruments	—			(1.6		)	—			—			(1.6		)
Depreciation and amortization	—			7.5			0.2			—			7.7
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	1.2			18.5			2.9			(0.6		)	22
Net periodic pension benefit income relating to VEBAs	—			(6.1		)	—			—			(6.1		)
Total selling, administrative, research and development, and general	1.2			12.4			2.9			(0.6		)	15.9
Other operating charges, net	—			0.2			—			—			0.2
Total costs and expenses	1.2			289.3			32.8			(25.6		)	297.7
Operating (loss) income	(1.2		)	46.4			1.2			—			46.4
Other (expense) income:
Interest expense	(9.3		)	—			—			0.1			(9.2		)
Other income, net	0.4			0.8			0.7			(0.1		)	1.8
(Loss) income before income taxes	(10.1		)	47.2			1.9			—			39
Income tax (provision) benefit	—			(17.8		)	(0.5		)	3.8			(14.5		)
Earnings in equity of subsidiaries	34.6			1.4			—			(36.0		)	—
Net income	$	24.5		$	30.8		$	1.4		$	(32.2	)	$	24.5
Comprehensive income	$	26.6		$	33		$	1.3		$	(34.3	)	$	26.6
CONDENSED CONSOLIDATING STATEMENT OF COMPREHESIVE INCOME
Six Months Ended June 30, 2014
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	662.8		$	67.1		$	(50.7	)	$	679.2
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			549.7			58.1			(49.4		)	558.4
Unrealized gains on derivative instruments	—			(3.6		)	—			—			(3.6		)
Depreciation and amortization	—			14.6			0.5			—			15.1
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	2.2			35.1			6.2			(1.2		)	42.3
Net periodic pension benefit income relating to VEBAs	—			(11.7		)	—			—			(11.7		)
Total selling, administrative, research and development, and general	2.2			23.4			6.2			(1.2		)	30.6
Other operating charges, net	—			0.2			—			—			0.2
Total costs and expenses	2.2			584.3			64.8			(50.6		)	600.7
Operating (loss) income	(2.2		)	78.5			2.3			(0.1		)	78.5
Other (expense) income:
Interest expense	(18.6		)	0.4			—			0.2			(18.0		)
Other income, net	1.4			2			0.5			(0.2		)	3.7
(Loss) income before income taxes	(19.4		)	80.9			2.8			(0.1		)	64.2
Income tax (provision) benefit	—			(30.4		)	(0.8		)	7.3			(23.9		)
Earnings in equity of subsidiaries	59.7			1.8			—			(61.5		)	—
Net income	$	40.3		$	52.3		$	2		$	(54.3	)	$	40.3
Comprehensive income	$	43.3		$	55.2		$	2.1		$	(57.3	)	$	43.3
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Quarter Ended June 30, 2013
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	324.7		$	29.6		$	(25.4	)	$	328.9
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			258.9			26.3			(23.7		)	261.5
Unrealized losses on derivative instruments	—			4.2			—			—			4.2
Depreciation and amortization	—			6.8			0.2			—			7
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	1.1			20.2			2.1			(1.6		)	21.8
Net periodic pension benefit income relating to VEBAs	—			(5.7		)	—			—			(5.7		)
Total selling, administrative, research and development, and general	1.1			14.5			2.1			(1.6		)	16.1
Total costs and expenses	1.1			284.4			28.6			(25.3		)	288.8
Operating (loss) income	(1.1		)	40.3			1			(0.1		)	40.1
Other (expense) income:
Interest expense	(9.0		)	—			—			—			(9.0		)
Other (expense) income, net	(0.9		)	0.3			(0.2		)	—			(0.8		)
(Loss) income before income taxes	(11.0		)	40.6			0.8			(0.1		)	30.3
Income tax (provision) benefit	—			(15.1		)	(0.7		)	4.1			(11.7		)
Earnings (losses) in equity of subsidiaries	29.6			(0.1		)	—			(29.5		)	—
Net income	$	18.6		$	25.4		$	0.1		$	(25.5	)	$	18.6
Comprehensive income	$	19.9		$	26.3		$	0.5		$	(26.8	)	$	19.9
CONDENSED CONSOLIDATING STATEMENT OF COMPREHESIVE INCOME
Six Months Ended June 30, 2013
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	656.5		$	60		$	(50.2	)	$	666.3
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			518.6			53.3			(46.8		)	525.1
Unrealized losses on derivative instruments	—			4.9			—			—			4.9
Depreciation and amortization	—			13.5			0.5			—			14
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	1.5			40.6			4.5			(3.1		)	43.5
Net periodic pension benefit income relating to VEBAs	—			(11.3		)	—			—			(11.3		)
Total selling, administrative, research and development, and general	1.5			29.3			4.5			(3.1		)	32.2
Total costs and expenses	1.5			566.3			58.3			(49.9		)	576.2
Operating (loss) income	(1.5		)	90.2			1.7			(0.3		)	90.1
Other (expense) income:
Interest expense	(18.1		)	(0.3		)	—			0.1			(18.3		)
Other (expense) income, net	(0.5		)	0.9			(0.1		)	(0.1		)	0.2
(Loss) income before income taxes	(20.1		)	90.8			1.6			(0.3		)	72
Income tax (provision) benefit	—			(34.1		)	6.5			7.7			(19.9		)
Earnings in equity of subsidiaries	72.2			7.7			—			(79.9		)	—
Net income	$	52.1		$	64.4		$	8.1		$	(72.5	)	$	52.1
Comprehensive income	$	54.6		$	66.1		$	8.9		$	(75.0	)	$	54.6
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
Six Months Ended June 30, 2014
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Cash flows from operating activities:
Net cash provided by operating activities	$	7.6		$	56.9		$	6.8		$	—		$	71.3
Cash flows from investing activities:
Capital expenditures	—			(29.4		)	(0.7		)	—			(30.1		)
Purchase of available for sale securities	—			(23.4		)	—			—			(23.4		)
Proceeds from disposition of available for sale securities	—			25			—			—			25
Net cash used in investing activities	—			(27.8		)	(0.7		)	—			(28.5		)
Cash flows from financing activities:
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	—			0.8			—			—			0.8
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	(2.4		)	—			—			—			(2.4		)
Repurchase of common stock	(23.7		)	—			—			—			(23.7		)
Cash dividend paid to stockholders	(12.8		)	—			—			—			(12.8		)
Intercompany loan	31.3			(22.9		)	(8.4		)	—			—
Net cash used in financing activities	(7.6		)	(22.1		)	(8.4		)	—			(38.1		)
Net increase (decrease) in cash and cash equivalents during the period	—			7			(2.3		)	—			4.7
Cash and cash equivalents at beginning of period	5			157.7			6.8			—			169.5
Cash and cash equivalents at end of period	$	5		$	164.7		$	4.5		$	—		$	174.2
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
Six Months Ended June 30, 2013
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$	(14.4	)	$	60.4		$	2.9		$	—		$	48.9
Cash flows from investing activities:
Capital expenditures	—			(25.0		)	(1.0		)	—			(26.0		)
Purchase of available for sale securities	—			(98.2		)	—			—			(98.2		)
Proceeds from sale of available for sale securities	—			135.7			—			—			135.7
Change in restricted cash	—			0.7			—			—			0.7
Net cash provided by (used in) investing activities	—			13.2			(1.0		)	—			12.2
Cash flows from financing activities:
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	—			0.9			—			—			0.9
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	(2.2		)	—			—			—			(2.2		)
Repurchase of common stock	(39.9		)	—			—			—			(39.9		)
Cash dividend paid to stockholders	(11.6		)	—			—			—			(11.6		)
Intercompany loan	68.1			(64.8		)	(3.3		)	—			—
Net cash provided by (used in) financing activities	14.4			(63.9		)	(3.3		)	—			(52.8		)
Net increase (decrease) in cash and cash equivalents during the period	—			9.7			(1.4		)	—			8.3
Cash and cash equivalents at beginning of period	5			266			2.4			—			273.4
Cash and cash equivalents at end of period	$	5		$	275.7		$	1		$	—		$	281.7

Subsequent_Events

Subsequent Events	6 Months Ended
	Jun. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	Subsequent Events
	Dividend Declaration. On July 15, 2014, the Company announced that its Board of Directors declared a cash dividend of $0.35 per common share or approximately $6.3 (including dividend equivalents), which will be paid on or about August 15, 2014 to stockholders of record at the close of business on July 25, 2014.
	Anti-dilution Adjustments to Convertible Notes and Convertible Note Hedge Transactions. Based on the Company’s closing stock price for its common stock on the ex-dividend date for the quarterly dividend declared on July 15, 2014, (a) the Convertible Notes’ conversion rate will be 20.8862 shares per $1,000 principal amount of the Convertible Notes and the equivalent conversion price will be $47.88 per share, (b) the Call Options’ exercise price will be approximately $47.88 per share, and (c) the Warrants’ exercise price will each be $60.80 per share.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Organization and Nature of Operations	'
	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 11 for additional information regarding the Company’s reportable segment and its other business units.
Principles of Consolidation and Basis of Presentation	'
	Principles of Consolidation and Basis of Presentation. The accompanying unaudited 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”) applicable for interim periods and, therefore, do not include all information and footnotes required by GAAP for complete financial statements. In management’s opinion, all adjustments (which include normal recurring adjustments) considered necessary for a fair presentation have been included. The results of operations for the Company’s interim periods are not necessarily indicative of the results of operations that may be achieved for the entire 2014 fiscal year. The financial information as of December 31, 2013 is derived from the Company’s audited consolidated financial statements and footnotes for the year ended December 31, 2013 included in the Company’s Annual Report on Form 10-K.
Use of Estimates in the Preparation of Financial Statements	'
	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.
Inventories	'
	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. During the quarter and six months ended June 30, 2014, the Company decremented a prior year, higher cost LIFO layer which resulted in charges of $0.6 and $2.4, respectively. The excess of current cost over the stated LIFO value of inventory at June 30, 2014 and December 31, 2013 was $17.4 and $0.4, respectively. 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 June 30, 2014 and December 31, 2013 were included in the Fabricated Products segment (see Note 2 for the components of inventories).
Property, Plant and Equipment - Net	'
	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 on 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 $0.8 and $0.7 during the quarters ended June 30, 2014 and June 30, 2013, respectively. The amount of interest expense capitalized as construction in progress was $1.9 and $1.1 for the six months ended June 30, 2014 and June 30, 2013, 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. For the quarters ended June 30, 2014 and June 30, 2013, the Company recorded depreciation expense of $7.3 and $6.5, respectively, relating to the Company’s operating facilities in its Fabricated Products segment. For the six months ended June 30, 2014 and June 30, 2013, the Company recorded depreciation expense of $14.1 and $13.0, respectively, relating to the Company’s operating facilities in its Fabricated Products segment. An immaterial amount of depreciation expense was also recorded relating to the Company’s All Other business unit for all periods presented in this Report.
New Accounting Pronouncements	'
	New Accounting Pronouncements. Accounting Standards Update ASU No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. (“ASU 2013-11”), was issued in July 2013. ASU 2013-11 requires an entity to present in the financial statements an unrecognized tax benefit, or a portion of an unrecognized tax benefit, as a reduction to a deferred tax asset resulting from a net operating loss carryforward, a similar tax loss, or a tax credit carryforward. However, when the above situation is not available at the reporting date or the tax law of the applicable jurisdiction does not require the entity to use the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. An entity is required to adopt ASU 2013-11 for annual and interim periods beginning after December 15, 2013. The Company’s adoption of ASU 2013-11 in the first quarter of 2014 did not have a material impact on its financial statements.
	ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”), was issued in May 2014. ASU 2014-09 requires an entity to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve this core principle, the guidance provides that an entity should apply the following steps: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the entity satisfies a performance obligation. The Company expects to adopt ASU 2014-09 for the fiscal year ending December 31, 2016 and the Company will continue to assess the impact on its financial statements.
	ASU No. 2014-12, Compensation-Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period - Consensus of the FASB Emerging Issues Task Force (“ASU 2014-12”), was issued in June 2014. ASU 2014-12 requires an entity to treat a performance target that affects vesting and that could be achieved after the requisite service period as a performance condition. The performance target should not be reflected in estimating the grant-date fair value of the award. Additionally, compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved, and should represent the compensation cost attributable to the period(s) for which the requisite service has already been rendered; if the performance target becomes probable of being achieved before the end of the requisite service period, then the remaining unrecognized compensation cost should be recognized prospectively over the remaining requisite service period. Finally, the total amount of compensation cost recognized during and after the requisite service period should reflect the number of awards that are expected to vest, and should be adjusted to reflect those awards that ultimately vest. An entity is required to adopt ASU 2014-12 for annual and interim periods beginning after December 15, 2015. The Company does not expect the adoption of ASU 2014-12 to have a material impact on its financial statements.

Supplemental_Balance_Sheet_Inf1

Supplemental Balance Sheet Information (Tables)	6 Months Ended
	Jun. 30, 2014
Supplemental Balance Sheet Information [Abstract]	'
Cash and Cash Equivalents	'
		June 30, 2014			December 31, 2013
	Cash and Cash Equivalents.
	Cash and money market funds	$	69.7		$	57.7
	Commercial paper	104.5			111.8
	Total	$	174.2		$	169.5
Trade Receivables	'
	Trade Receivables.
	Billed trade receivables	$	123.7		$	120.2
	Unbilled trade receivables	0.2			0.4
	Trade receivables, gross	123.9			120.6
	Allowance for doubtful receivables	(0.8		)	(0.8		)
	Trade receivables, net	$	123.1		$	119.8
Inventories	'
	Inventories.
	Finished products	$	60.4		$	72.5
	Work-in-process	64.3			75.9
	Raw materials	53.3			47.2
	Operating supplies and repair and maintenance parts	20.1			18.8
	Total	$	198.1		$	214.4
Prepaid Expenses and Other Current Assets	'
	Prepaid Expenses and Other Current Assets.
	Current derivative assets – Notes 8 and 9	$	90.3		$	2
	Current deferred tax assets	36.7			36.7
	Short-term restricted cash	0.3			0.3
	Prepaid taxes	1.8			—
	Other	6.4			5.2
	Total	$	135.5		$	44.2
Property, Plant and Equipment - Net	'
	Property, Plant and Equipment - Net.
	Land and improvements	$	22.8		$	22.6
	Buildings and leasehold improvements	54.7			53
	Machinery and equipment	491.2			425.6
	Construction in progress	24.7			66
	Active property, plant and equipment, gross	593.4			567.2
	Accumulated depreciation	(152.0		)	(137.9		)
	Total	$	441.4		$	429.3
Other Assets	'
	Other Assets.
	Derivative assets – Notes 8 and 9	$	0.3		$	79.8
	Restricted cash	9.3			9.3
	Deferred financing costs	6.7			8.9
	Deferred compensation plan assets	7.4			6.5
	Other	0.3			0.3
	Total	$	24		$	104.8
Other Accrued Liabilities	'
	Other Accrued Liabilities.
	Current derivative liabilities – Notes 8 and 9	$	89.5		$	1.8
	Uncleared cash disbursements	9.1			9.6
	Accrued income taxes and taxes payable	6.3			4.6
	Accrued annual VEBA contribution	—			16
	Short-term environmental accrual – Note 7	3.6			2.8
	Accrued interest	3.6			3.7
	Other	3			6.3
	Total	$	115.1		$	44.8
Long-term Liabilities	'
	Long-Term Liabilities.
	Derivative liabilities – Notes 8 and 9	$	0.5		$	84.3
	Income tax liabilities	5.2			5
	Workers’ compensation accruals	24.4			23.3
	Long-term environmental accrual – Note 7	18.6			20
	Long-term asset retirement obligations	4.3			4
	Deferred compensation liability	7.7			7
	Long-term capital lease	0.1			0.1
	Other long-term liabilities	2.9			2.7
	Total	$	63.7		$	146.4
Long-term Debt	'
	Long-Term Debt — Note 3.
	Senior notes	$	225		$	225
	Cash convertible senior notes	—			163.5
	Total	$	225		$	388.5

LongTerm_Debt_and_Credit_Facil1

Long-Term Debt and Credit Facility (Tables)	6 Months Ended
	Jun. 30, 2014
Debt Disclosure [Abstract]	'
Principal amount, carrying amount, and interest expense of the notes	'											[1]
	The following tables provide additional information regarding the Convertible Notes:
		June 30, 2014			December 31, 2013
	Principal amount	$	175		$	175
	Less: unamortized issuance discount	(7.1		)	(11.5		)
	Carrying amount, net of discount	$	167.9		$	163.5
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014		2013
	Contractual coupon interest	$	1.9		$	1.9		$	3.9	$	3.9
	Amortization of discount	2.3			2.1			4.4		4
	Amortization of deferred financing costs	0.3			0.3			0.6		0.6
	Total interest expense1	$	4.5		$	4.3		$	8.9	$	8.5
	____________
	1	A portion of the interest relating to the Convertible Notes is capitalized as Construction in progress.
[1]	A portion of the interest relating to the Convertible Notes is capitalized as Construction in progress.

Income_Tax_Matters_Tables

Income Tax Matters (Tables)	6 Months Ended
	Jun. 30, 2014
Income Tax Disclosure [Abstract]	'
Tax Provision	'
	The provision for incomes taxes, for each period presented, consisted of the following:
		Quarter Ended				Six Months Ended
		June 30,				June 30,
		2014		2013		2014		2013
	Domestic	$	13.9	$	11.1	$	23	$	26.5
	Foreign	0.6		0.6		0.9		(6.6		)
	Total	$	14.5	$	11.7	$	23.9	$	19.9

Employee_Benefits_Tables

Employee Benefits (Tables)	6 Months Ended
	Jun. 30, 2014
Compensation and Retirement Disclosure [Abstract]	'
Schedule of (Income) Charges Related to Benefit Plans	'
	The following table presents the components of net periodic pension benefit income for the VEBAs and charges relating to all other employee benefit plans for the quarter and six months ended June 30, 2014 and June 30, 2013:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	VEBAs:
	Service cost	$	0.5		$	0.7		$	1.1		$	1.3
	Interest cost	4.2			3.7			8.3			7.3
	Expected return on plan assets	(12.8		)	(11.5		)	(25.6		)	(22.7		)
	Amortization of prior service cost	2.6			1			5.4			2.1
	Amortization of net actuarial (gain) loss	(0.6		)	0.4			(0.9		)	0.7
	Total net periodic pension benefit (income) expense relating to VEBAs	(6.1		)	(5.7		)	(11.7		)	(11.3		)
	Deferred compensation plan	0.4			—			0.6			0.4
	Defined contribution plans	1.5			1.3			5.5			5.3
	Multiemployer pension plans	0.9			0.9			1.8			1.7
	Total	$	(3.3	)	$	(3.5	)	$	(3.8	)	$	(3.9	)
Allocation of (Income) Charges Relating to Benefit Plans by Segment	'
	(see Note 11):
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Fabricated Products	$	2.3		$	2		$	6.9		$	6.6
	All Other	(5.6		)	(5.5		)	(10.7		)	(10.5		)
	Total	$	(3.3	)	$	(3.5	)	$	(3.8	)	$	(3.9	)

Employee_Incentive_Plans_Table

Employee Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Compensation expense relating to short term incentive plans	'
	Total costs relating to STI Plans were recorded as follows, for each period presented:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Cost of products sold, excluding depreciation and amortization and other items	$	1.4		$	1.3		$	2.5			$	2.4
	Selling, administrative, research and development, and general	3.2			3.5			4.5				6.5
	Total costs recorded in connection with STI Plans	$	4.6		$	4.8		$	7			$	8.9
	The following table presents the allocation of the charges detailed above, by segment:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Fabricated Products	$	3.5		$	3.3		$	5.4			$	6.2
	All Other	1.1			1.5			1.6				2.7
	Total costs recorded in connection with STI Plans	$	4.6		$	4.8		$	7			$	8.9
Non-cash compensation expense	'
	Non-cash compensation expense by type of award under LTI Programs were as follows, for each period presented:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Service-based non-vested common shares and restricted stock units	$	1.2		$	0.8		$	2.3			$	2.5
	Performance shares	0.5			1.1			1				2
	Market-based shares	0.6			—			1				—
	Total non-cash compensation expense	$	2.3		$	1.9		$	4.3			$	4.5
	The following table presents the allocation of the charges detailed above, by segment:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014				2013
	Fabricated Products	$	1.1		$	0.6		$	2.1			$	1.2
	All Other	1.2			1.3			2.2				3.3
	Total non-cash compensation expense	$	2.3		$	1.9		$	4.3			$	4.5
Unrecognized gross compensation cost data	'
	The following table presents unrecognized gross compensation cost data as of June 30, 2014:
		Unrecognized gross compensation costs, by award type			Expected period (in years) over which the remaining gross compensation costs will be recognized, by award type
	Service-based non-vested common shares and restricted stock units	$	9.5		2.9
	Performance shares	$	3		1.5
	Market-based shares	$	5.7		2.6
Summary of activity of non-vested common shares, restricted stock units, and performance shares	'
	A summary of the activity with respect to non-vested common shares, restricted stock units and performance shares for the six months ended June 30, 2014 is as follows:
		Non-Vested					Restricted							Performance				Performance Shares (Market-Based)
		Common Shares					Stock Units							Shares
		Shares		Weighted-Average			Units			Weighted-Average				Shares		Weighted-Average		Shares		Weighted-Average
				Grant-Date Fair						Grant-Date Fair						Grant-Date Fair				Grant-Date Fair
				Value per Share						Value per Unit						Value per Share				Value per Share
	Outstanding at December 31, 2013	143,967		$	51.09		5,472			$	51.03			562,554		$	49.26	—		—
	Granted	118,638		66.31			2,235			67.42				—		—		160,868		83.18
	Vested	(62,659	)	52.43			(2,350	)		46.83				(42,545	)	47.04		—		—
	Forfeited	(526	)	55.03			—			—				(1,682	)	50.4		(235	)	83.18
	Canceled	—		—			—			—				(139,384	)	46.77		—		—
	Outstanding at June 30, 2014	199,420		$	59.71		5,357			$	59.71			378,943		$	50.43	160,633		83.18
	A summary of select activity with respect to non-vested common shares, restricted stock units and performance shares for the six months ended June 30, 2013 is as follows:
		Non-Vested					Restricted							Performance
		Common Shares					Stock Units							Shares
		Shares		Weighted-Average			Units			Weighted-Average				Shares		Weighted-Average
				Grant-Date Fair						Grant-Date Fair						Grant-Date Fair
				Value per Share						Value per Unit						Value per Share
	Granted	74,236		$	58.49		2,600			$	57.7			170,298		$	57.57
	Vested	(81,161	)	$	41.67		(2,311	)		$	42.74			(32,312	)	$	34.13

Derivative_Financial_Instrumen1

Derivative Financial Instruments and Related Hedging Programs (Tables)	6 Months Ended
	Jun. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Summary of realized and unrealized gains and losses	'
	Realized and unrealized gains (losses) associated with all derivative contracts consisted of the following, for each period presented:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Realized gains (losses):
	Aluminum	$	1.3		$	(1.6	)	$	2.1		$	(1.6	)
	Natural Gas	0.5			(0.1		)	1.2			(0.8		)
	Electricity	(0.5		)	(0.1		)	—			(0.1		)
	Total realized gains (losses)	$	1.3		$	(1.8	)	$	3.3		$	(2.5	)
	Unrealized gains (losses):
	Aluminum	$	0.6		$	(1.8	)	$	2.3		$	(6.2	)
	Natural Gas	(0.2		)	(1.9		)	0.6			0.8
	Electricity	1.2			(0.6		)	0.7			0.6
	Foreign Currency	(0.1		)	0.1			(0.1		)	(0.1		)
	Call Options relating to the Convertible Notes	2.5			(9.1		)	6.9			(3.1		)
	Bifurcated Conversion Feature of the Convertible Notes	(2.0		)	8.2			(5.5		)	2.6
	Total unrealized gains (losses)	$	2		$	(5.1	)	$	4.9		$	(5.4	)
Summary of material derivative positions	'
	The following table summarizes the Company’s material derivative positions at June 30, 2014:
	Aluminum		Maturity Period (month/year)	Notional Amount of contracts (mmlbs)
	Fixed price purchase contracts		7/14 through 12/15	44.1
	Fixed price sales contracts		7/14 through 12/14	1.3
	Midwest premium swap contracts1		7/14 through 12/15	42.3
	Natural Gas2		Maturity Period (month/year)	Notional Amount of contracts (mmbtu)
	Fixed price purchase contracts		7/14 through 12/16	6,150,000
	Electricity		Maturity Period (month/year)	Notional Amount of contracts (Mwh)
	Fixed price purchase contracts		7/14 through 12/15	285,625
	Hedges Relating to the Convertible Notes		Contract Period (month/year)	Notional Amount of contracts (Common Shares)
	Bifurcated Conversion Feature3		3/10 through 3/15	3,649,608
	Call Options3		3/10 through 3/15	3,649,608
	______________________
	1	Regional premiums represent the premium over the London Metal Exchange price for primary aluminum which is incurred on the Company’s purchases of primary aluminum.
	2	As of June 30, 2014, the Company’s exposure to fluctuations in natural gas prices had been substantially reduced for approximately 88%, 82% and 30% of the expected natural gas purchases for the remainder of 2014, 2015 and 2016, respectively.
	3	The Bifurcated Conversion Feature represents the cash conversion feature of the Convertible Notes. The Call Options expire on the maturity or earlier conversion of the Convertible Notes and have an exercise price equal to the conversion price of the Convertible Notes, subject to anti-dilution adjustments substantially similar to the anti-dilution adjustments for the Convertible Notes. Although the fair value of the Call Options is derived from a notional number of shares of the Company’s common stock, the Call Options may only be settled in cash.
Summary of offsetting derivative instruments by counterparty	'
	The following tables present offsetting information regarding the Company’s derivatives by type of counterparty as of June 30, 2014:
	Derivative Assets and Collateral Held by Counterparty
											Gross Amounts Not Offset in the Consolidated Balance Sheets
		Gross Amounts of Recognized Assets			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Assets Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Received		Net Amount
	Counterparty (with Netting Agreements)	$	2		$	—		$	2		$	0.8		$	—	$	1.2
	Counterparty (without Netting Agreements)1	87.6			—			87.6			—			—		87.6
	Counterparty (with partial Netting Agreements)	1			—			1			0.3			—		0.7
	Total	$	90.6		$	—		$	90.6		$	1.1		$	—	$	89.5
	Derivative Liabilities and Collateral Held by Counterparty
											Gross Amounts Not Offset in the Consolidated Balance Sheets
		Gross Amounts of Recognized Liabilities			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Liabilities Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Pledged		Net Amount
	Counterparty (with Netting Agreements)	$	(0.8	)	$	—		$	(0.8	)	$	(0.8	)	$	—	$	—
	Counterparty (without Netting Agreements)1	(88.7		)	—			(88.7		)	—			—		(88.7		)
	Counterparty (with partial Netting Agreements)	(0.5		)	—			(0.5		)	(0.3		)	—		(0.2		)
	Total	$	(90.0	)	$	—		$	(90.0	)	$	(1.1	)	$	—	$	(88.9	)
	_________________
	1	Such amounts include the fair value of the Bifurcated Conversion Feature and Call Options at June 30, 2014 (see Note 9).
	The following tables present offsetting information regarding the Company’s derivatives by type of counterparty as of December 31, 2013:
	Derivative Assets and Collateral Held by Counterparty
											Gross Amounts Not Offset in the Consolidated Balance Sheets
		Gross Amounts of Recognized Assets			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Assets Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Received		Net Amount
	Counterparty (with Netting Agreements)	$	1		$	—		$	1		$	0.8		$	—	$	0.2
	Counterparty (without Netting Agreements)1	80.4			—			80.4			—			—		80.4
	Counterparty (with partial Netting Agreements)	0.4			—			0.4			0.4			—		—
	Total	$	81.8		$	—		$	81.8		$	1.2		$	—	$	80.6
	Derivative Liabilities and Collateral Held by Counterparty
											Gross Amounts Not Offset in the Consolidated Balance Sheets
		Gross Amounts of Recognized Liabilities			Gross Amounts Offset in the Consolidated Balance Sheets			Net Amounts of Liabilities Presented in the Consolidated Balance Sheets			Financial Instruments			Cash Collateral Pledged		Net Amount
	Counterparty (with Netting Agreements)	$	(1.6	)	$	—		$	(1.6	)	$	(0.8	)	$	—	$	(0.8	)
	Counterparty (without Netting Agreements)1	(83.2		)	—			(83.2		)	—			—		(83.2		)
	Counterparty (with partial Netting Agreements)	(1.3		)	—			(1.3		)	(0.4		)	—		(0.9		)
	Total	$	(86.1	)	$	—		$	(86.1	)	$	(1.2	)	$	—	$	(84.9	)
	_________________
	1	Such amounts include the fair value of the Bifurcated Conversion Feature and Call Options at December 31, 2013 (see Note 9).

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2014
Fair Value Disclosures [Abstract]	'
Assumptions used in determining fair value of the Call Option	'
	The Company determines the fair value of the Call Options using a binomial lattice valuation model. The inputs to the model at June 30, 2014 were as follows:
	The Company’s stock price at June 30, 2014	$	72.87
	Quarterly dividend yield (per share) upon purchase of the Call Option1	$	0.24
	Risk-free interest rate2	0.08		%
	Credit spread (basis points)3	130
	Expected volatility rate4	17		%
	______________________
	1	The quarterly dividend in the second quarter of 2014 was $0.35 per share, but the model assumes a $0.24 per share quarterly dividend as was paid at the inception of the Call Options. Quarterly dividends in excess of $0.24 per share do not affect the Call Options’ value due to anti-dilution adjustments.
	2	The risk-free rate was based on the six-month Constant Maturity Treasury rate and one-year Constant Maturity Treasury rate on June 30, 2014.
	3	The credit spread is based on the Company’s long-term credit rating of BB issued by Standard & Poor’s.
	4	The volatility rate was based on both observed volatility, which is based on the Company’s historical stock price, and implied volatility from the Company’s traded options. Such volatility was further adjusted to take into consideration market participant risk tolerance.
Summary of assets and liabilities measured and recognized at fair value on a recurring basis	'
	The following table presents the Company’s financial instruments, classified under the appropriate level of the fair value hierarchy, as of June 30, 2014:
		Level 1			Level 2			Level 3		Total
	FINANCIAL ASSETS:
	Derivative Instruments:
	Aluminum -
	Fixed price purchase contracts	$	—		$	0.8		$	—	$	0.8
	Midwest premium swap contracts	—			—			1.4		1.4
	Natural Gas -
	Fixed price purchase contracts	—			0.9			—		0.9
	Electricity -
	Fixed price purchase contracts	—			1			—		1
	Hedges Relating to the Convertible Notes -
	Call Options	—			86.5			—		86.5
	All Other Financial Assets:
	Cash and cash equivalents	69.7			104.5			—		174.2
	Short-term investments	—			127.2			—		127.2
	Deferred compensation plan asset	—			7.4			—		7.4
	Total assets	$	69.7		$	328.3		$	1.4	$	399.4
	FINANCIAL LIABILITIES:
	Derivative Instruments:
	Aluminum -
	Fixed price purchase contracts	$	—		$	(0.5	)	$	—	$	(0.5	)
	Natural Gas -
	Fixed price purchase contracts	—			(0.6		)	—		(0.6		)
	Electricity -
	Fixed price purchase contracts	—			(0.2		)	—		(0.2		)
	Hedges Relating to the Convertible Notes -
	Bifurcated Conversion Feature	—			(88.7		)	—		(88.7		)
	All Other Financial Liabilities:
	Senior Notes	(253.2		)	—			—		(253.2		)
	Convertible Notes	(269.7		)	—			—		(269.7		)
	Total liabilities	$	(522.9	)	$	(90.0	)	$	—	$	(612.9	)
	The following table presents the Company’s financial instruments, classified under the appropriate level of the fair value hierarchy, as of December 31, 2013:
		Level 1			Level 2			Level 3		Total
	FINANCIAL ASSETS:
	Derivative Instruments:
	Aluminum -
	Fixed price purchase contracts	$	—		$	0.1		$	—	$	0.1
	Midwest premium swap contracts	—			—			1.1		1.1
	Natural Gas -
	Fixed price purchase contracts	—			0.5			—		0.5
	Electricity -
	Fixed price purchase contracts	—			0.5			—		0.5
	Foreign Currency -
	Euro	—			0.1			—		0.1
	Hedges Relating to the Convertible Notes -
	Call Options	—			79.5			—		79.5
	All Other Financial Assets:
	Cash and cash equivalents	57.7			111.8			—		169.5
	Short-term investments	—			129.5			—		129.5
	Deferred compensation plan asset	—			6.5			—		6.5
	Total assets	$	57.7		$	328.5		$	1.1	$	387.3
	FINANCIAL LIABILITIES:
	Derivative Instruments:
	Aluminum -
	Fixed price purchase contracts	$	—		$	(1.8	)	$	—	$	(1.8	)
	Natural Gas -
	Fixed price purchase contracts	—			(0.8		)	—		(0.8		)
	Electricity -
	Fixed price purchase contracts	—			(0.4		)	—		(0.4		)
	Hedges Relating to the Convertible Notes -
	Bifurcated Conversion Feature	—			(83.1		)	—		(83.1		)
	All Other Financial Liabilities:
Senior Notes	(255.4		)	—			—		(255.4		)
Convertible Notes	(260.0		)	—			—		(260.0		)
Total liabilities	$	(515.4	)	$	(86.1	)	$	—	$	(601.5	)
Reconciliation of activity for financial instruments classified as Level 3	'
	The following table presents a reconciliation of activity for the Midwest premium derivative contracts on a net basis:
		Level 3
	Balance at December 31, 2013	$	1.1
	Total realized/unrealized gains included in:
	Cost of goods sold excluding depreciation and amortization and other items and Unrealized (gains) losses on derivative instruments	4.1
	Transactions involving Level 3 derivative contracts:
	Purchases	0.6
	Sales	—
	Issuances	—
	Settlements	(4.4		)
	Transactions involving Level 3 derivatives — net	(3.8		)
	Transfers in and (or) out of Level 3 valuation hierarchy	—
	Balance at June 30, 2014	$	1.4
	Total gains included in Unrealized (gains) losses on derivative instruments, attributable to the change in unrealized gains/losses relating to derivative contracts held at June 30, 2014:	$	1.1

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Calculation of basic and diluted earnings per share	'
	Basic and diluted earnings per share were calculated as follows, for each period presented:
		Quarter Ended				Six Months Ended
		June 30,				June 30,
		2014		2013		2014		2013
	Numerator:
	Net income	$	24.5	$	18.6	$	40.3	$	52.1
	Denominator — Weighted-average common shares outstanding (in thousands):
	Basic1	17,841		18,742		17,889		19,027
	Add: dilutive effect of non-vested common shares, restricted stock units and performance shares	112		112		133		135
	Add: dilutive effect of warrants	505		91		490		94
	Diluted2	18,458		18,945		18,512		19,256
	Earnings per common share, Basic:
	Net income per share	$	1.38	$	0.99	$	2.25	$	2.73
	Earnings per common share, Diluted:
	Net income per share	$	1.33	$	0.98	$	2.18	$	2.7
	______________________
	1	The basic weighted-average number of common shares outstanding during the period excludes non-vested common shares, restricted stock units, performance shares and market-based shares.
	2	The diluted weighted-average number of common shares outstanding during the periods were calculated using the treasury method.

Segment_Information_Tables

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2014
Segment Reporting [Abstract]	'
Summary of financial information by operating segment	'
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Net sales:
	Fabricated Products	$	344.1		$	328.9		$	679.2		$	666.3
	Segment operating income (loss):
	Fabricated Products 1,2	$	50.2		$	45		$	85.6		$	100.2
	All Other3	(3.8		)	(4.9		)	(7.1		)	(10.1		)
	Total operating income	$	46.4		$	40.1		$	78.5		$	90.1
	Interest expense	(9.2		)	(9.0		)	(18.0		)	(18.3		)
	Other income, net	1.8			(0.8		)	3.7			0.2
	Income before income taxes	$	39		$	30.3		$	64.2		$	72
	Depreciation and amortization:
	Fabricated Products	$	7.7		$	6.9		$	14.9		$	13.8
	All Other	—			0.1			0.2			0.2
	Total depreciation and amortization	$	7.7		$	7		$	15.1		$	14
	Capital expenditures:
	Fabricated Products	$	14.2		$	16.5		$	29.5		$	25.4
	All Other	0.5			0.2			0.6			0.6
	Total capital expenditures	$	14.7		$	16.7		$	30.1		$	26
	Income taxes paid:
	Fabricated Products —
	United States	$	0.1		$	0.3		$	0.2		$	0.6
	Canada	0.3			0.3			0.9			0.7
	Total income taxes paid	$	0.4		$	0.6		$	1.1		$	1.3
	______________________
	1.	Operating results in the Fabricated Products segment for the quarter ended June 30, 2014 included a charge of $0.6 as a result of decrementing a prior year, higher cost LIFO layer. Operating results in the Fabricated Products segment for the six months ended June 30, 2014 included a charge of $2.4 as a result of decrementing a prior year, higher cost layer.
	2.	Fabricated Products segment operating income included non-cash mark-to-market gains (losses) on primary aluminum, natural gas, electricity and foreign currency hedging activities totaling $1.5 and $(4.2) for the quarters ended June 30, 2014 and June 30, 2013, respectively. Non-cash mark-to-market gains (losses) on primary aluminum, natural gas, electricity and foreign currency hedging activities totaled $3.5 and $(4.9) for the six months ended June 30, 2014 and June 30, 2013, respectively. For further discussion regarding mark-to-market matters, see Note 8.
	3.	Operating loss in All Other included VEBA net periodic pension benefit income of $6.1 and $5.7 for the quarters ended June 30, 2014 and June 30, 2013, respectively. VEBA net periodic pension benefit income was $11.7 and $11.3 for the six months ended June 30, 2014 and June 30, 2013, respectively.
		June 30, 2014			December 31, 2013
	Assets:
	Fabricated Products	$	851.4		$	852.5
	All Other1	921.2			918.4
	Total assets	$	1,772.60		$	1,770.90
	_____________________
	1.	Assets in All Other represent primarily all of the Company’s cash and cash equivalents, short-term investments, financial derivative assets, net assets in respect of VEBA(s) (see Note 5) and net deferred income tax assets.
Schedule of net sales by end market segment applications	'
	Net sales by product categories, which are based on end market applications, for the Fabricated Products segment are as follows:
		Quarter Ended						Six Months Ended
		June 30,						June 30,
		2014			2013			2014			2013
	Net sales:
	Aero/HS products	$	173		$	165.1		$	336.6		$	344.7
	GE products	107.3			110.2			219.5			216
	Automotive Extrusions	44.7			31			85.5			61.8
	Other products	19.1			22.6			37.6			43.8
	Total net sales	$	344.1		$	328.9		$	679.2		$	666.3

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Tables)	6 Months Ended
	Jun. 30, 2014
Supplemental Cash Flow Elements [Abstract]	'
Supplemental Cash Flow Information	'
		Six Months Ended
		June 30,
		2014		2013
	Supplemental disclosure of cash flow information:
	Interest paid	$	12.1	$	14
	Income taxes paid	$	1.1	$	1.3
	Supplemental disclosure of non-cash transactions:
	Stock repurchases not yet settled (accrued in accounts payable)	$	0.3	$	0.6
	Non-cash capital expenditures	$	1.1	$	4.4
	Capital leases acquired	$	—	$	0.2

Other_Income_Expense_Net_Table

Other Income (Expense), Net (Tables)	6 Months Ended
	Jun. 30, 2014
Other Income and Expenses [Abstract]	'
Other Income (Expense), Net	'
	Other income (expense), net consisted of the following, for each period presented:
		Quarter Ended					Six Months Ended
		June 30,					June 30,
		2014		2013			2014		2013
	Interest income	$	0.2	$	—		$	0.5	$	0.1
	Unrealized gains (losses) on financial derivatives1	0.5		(0.9		)	1.4		(0.5		)
	Realized gains on investments	0.2		0.3			0.4		0.8
	All other, net	0.9		(0.2		)	1.4		(0.2		)
	Other non-operating income (expense), net	$	1.8	$	(0.8	)	$	3.7	$	0.2
	______________________
	1	See “Hedges Relating to the Convertible Notes” in Note 8 for discussion of such instruments.

Other_Comprehensive_Income_Tab

Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]	'
Other Comprehensive Income	'
	The following table presents the tax effect allocated to each component of Other comprehensive income for each period presented:
		Before-Tax			Income Tax			Net-of-Tax
		Amount			(Expense) Benefit3			Amount
	Quarter Ended June 30, 2014
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial gain1	$	(0.6	)	$	0.2		$	(0.4	)
	Amortization of prior service cost1	2.6			(1.0		)	1.6
	Other comprehensive income relating to VEBAs	2			(0.8		)	1.2
	Available for sale securities:
	Unrealized gains on available for sale securities	0.2			(0.1		)	0.1
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.1		)	0.1			—
	Other comprehensive income relating to available for sale securities	0.1			—			0.1
	Foreign currency translation adjustment	(0.1		)	—			(0.1		)
	Cumulative tax rate adjustment	—			0.9			0.9
	Other comprehensive income	$	2		$	0.1		$	2.1
	Quarter Ended June 30, 2013
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial loss1	$	0.4		$	(0.1	)	$	0.3
	Amortization of prior service cost1	1			(0.4		)	0.6
	Other comprehensive income relating to VEBAs	1.4			(0.5		)	0.9
	Available for sale securities:
	Unrealized gains on available for sale securities	0.2			(0.1		)	0.1
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.2		)	0.1			(0.1		)
	Other comprehensive income relating to available for sale securities	—			—			—
	Foreign currency translation adjustment	0.4			—			0.4
	Other comprehensive income	$	1.8		$	(0.5	)	$	1.3
	Six Months Ended June 30, 2014
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial gain1	$	(0.9	)	$	0.3		$	(0.6	)
	Amortization of prior service cost1	5.4			(2.0		)	3.4
	Other comprehensive income relating to VEBAs	4.5			(1.7		)	2.8
	Available for sale securities:
	Unrealized gains on available for sale securities	0.3			(0.1		)	0.2
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.2		)	0.1			(0.1		)
	Other comprehensive income relating to available for sale securities	0.1			—			0.1
	Foreign currency translation adjustment	0.1			—			0.1
	Other comprehensive income	$	4.7		$	(1.7	)	$	3
	Six Months Ended June 30, 2013
	VEBAs:
	Reclassification adjustments:
	Amortization of net actuarial loss1	$	0.7		$	(0.2	)	$	0.5
	Amortization of prior service cost1	2.1			(0.8		)	1.3
	Other comprehensive income relating to VEBAs	2.8			(1.0		)	1.8
	Available for sale securities:
	Unrealized gains on available for sale securities	0.5			(0.2		)	0.3
	Reclassification adjustments:
	Reclassification of unrealized gain upon sale of available for sale securities2	(0.6		)	0.2			(0.4		)
	Other comprehensive income relating to available for sale securities	(0.1		)	—			(0.1		)
	Foreign currency translation adjustment	0.8			—			0.8
	Other comprehensive income	$	3.5		$	(1.0	)	$	2.5
	________________
	1	Amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments were included as a component of Net periodic pension benefit income relating to VEBAs.
	2	Amounts reclassified out of Accumulated other comprehensive income relating to sales of available for sale securities were included as a component of Other income (expense), net. The Company uses the specific identification method to determine the amount reclassified out of accumulated other comprehensive income.
	3	Income tax amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments and sales of available for sale securities were included as a component of Income tax provision.

Guarantor_and_NonGuarantor_Fin1

Guarantor and Non-Guarantor Financial Statements (Tables)	6 Months Ended
	Jun. 30, 2014
Guarantor and Non-Guarantor Financial Statement [Abstract]	'
Schedule of Condensed Financial Statements	'
	CONDENSED CONSOLIDATING BALANCE SHEET
	June 30, 2014
		Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	ASSETS
	Current assets:
	Cash and cash equivalents	$	5		$	164.7		$	4.5		$	—		$	174.2
	Short-term investments	—			127.2			—			—			127.2
	Receivables:
	Trade, less allowance for doubtful receivables	—			119			4.1			—			123.1
	Intercompany receivables	—			26.1			0.7			(26.8		)	—
	Other	—			5.1			5.9			—			11
	Inventories	—			193.8			5.1			(0.8		)	198.1
	Prepaid expenses and other current assets	87.5			47.6			0.4			—			135.5
	Total current assets	92.5			683.5			20.7			(27.6		)	769.1
	Investments in and advances to subsidiaries	1,505.40			28.1			—			(1,533.5		)	—
	Property, plant, and equipment — net	—			425.9			15.5			—			441.4
	Long-term intercompany receivables	—			—			16.2			(16.2		)	—
	Net assets of VEBAs	—			422.2			—			—			422.2
	Deferred tax assets — net	—			36.9			—			8.9			45.8
	Intangible assets — net	—			32.9			—			—			32.9
	Goodwill	—			37.2			—			—			37.2
	Other assets	4.9			19			0.1			—			24
	Total	$	1,602.80		$	1,685.70		$	52.5		$	(1,568.4	)	$	1,772.60
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Current liabilities:
	Accounts payable	$	0.6		$	64.2		$	7.3		$	—		$	72.1
	Intercompany payable	23.4			8.5			2			(33.9		)	—
	Accrued salaries, wages, and related expenses	—			30.3			3.5			—			33.8
	Other accrued liabilities	92.2			21.7			1.2			—			115.1
	Current portion of long-term debt	167.9			—			—			—			167.9
	Short-term capital lease	—			0.1			—			—			0.1
	Total current liabilities	284.1			124.8			14			(33.9		)	389
	Deferred tax liability	—			—			1.2			—			1.2
	Long-term intercompany payable	—			16.2			—			(16.2		)	—
	Long-term liabilities	—			52.7			11			—			63.7
	Long-term debt	225			—			—			—			225
	Total liabilities	509.1			193.7			26.2			(50.1		)	678.9
	Total stockholders’ equity	1,093.70			1,492.00			26.3			(1,518.3		)	1,093.70
	Total	$	1,602.80		$	1,685.70		$	52.5		$	(1,568.4	)	$	1,772.60
	CONDENSED CONSOLIDATING BALANCE SHEET
	December 31, 2013
		Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
	ASSETS
	Current assets:
	Cash and cash equivalents	$	5		$	157.7		$	6.8		$	—		$	169.5
	Short-term investments	—			129.5			—			—			129.5
	Receivables:
	Trade, less allowance for doubtful receivables	—			117.7			2.1			—			119.8
	Intercompany receivables	—			0.1			0.2			(0.3		)	—
	Other	—			5.3			8.1			—			13.4
	Inventories	—			208.6			6.4			(0.6		)	214.4
	Prepaid expenses and other current assets	0.1			43.7			0.4			—			44.2
	Total current assets	5.1			662.6			24			(0.9		)	690.8
	Investments in and advances to subsidiaries	1,437.90			26.5			—			(1,464.4		)	—
	Property, plant, and equipment — net	—			414			15.3			—			429.3
	Long-term intercompany receivables	31.3			1.6			9.5			(42.4		)	—
	Net assets of VEBAs	—			406			—			—			406
	Deferred tax assets — net	—			60.2			—			8.9			69.1
	Intangible assets — net	—			33.7			—			—			33.7
	Goodwill	—			37.2			—			—			37.2
	Other assets	86.2			18.5			0.1			—			104.8
	Total	$	1,560.50		$	1,660.30		$	48.9		$	(1,498.8	)	$	1,770.90
	LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities:
Accounts payable	$	1.1		$	56.3		$	5.5		$	—		$	62.9
Intercompany payable	—			13.9			0.1			(14.0		)	—
Accrued salaries, wages, and related expenses	—			39.3			3.4			—			42.7
Other accrued liabilities	3.5			39.9			1.4			—			44.8
Short-term capital lease	—			0.2			—			—			0.2
Total current liabilities	4.6			149.6			10.4			(14.0		)	150.6
Deferred tax liability	—			—			1.2			—			1.2
Long-term intercompany payable	—			40.7			1.7			(42.4		)	—
Long-term liabilities	83.2			52			11.2			—			146.4
Long-term debt	388.5			—			—			—			388.5
Total liabilities	476.3			242.3			24.5			(56.4		)	686.7
Total stockholders’ equity	1,084.20			1,418.00			24.4			(1,442.4		)	1,084.20
Total	$	1,560.50		$	1,660.30		$	48.9		$	(1,498.8	)	$	1,770.90
CONDENSED CONSOLIDATING STATEMENT OF COMPREHESIVE INCOME
Quarter Ended June 30, 2014
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	335.7		$	34		$	(25.6	)	$	344.1
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			270.8			29.7			(25.0		)	275.5
Unrealized gains on derivative instruments	—			(1.6		)	—			—			(1.6		)
Depreciation and amortization	—			7.5			0.2			—			7.7
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	1.2			18.5			2.9			(0.6		)	22
Net periodic pension benefit income relating to VEBAs	—			(6.1		)	—			—			(6.1		)
Total selling, administrative, research and development, and general	1.2			12.4			2.9			(0.6		)	15.9
Other operating charges, net	—			0.2			—			—			0.2
Total costs and expenses	1.2			289.3			32.8			(25.6		)	297.7
Operating (loss) income	(1.2		)	46.4			1.2			—			46.4
Other (expense) income:
Interest expense	(9.3		)	—			—			0.1			(9.2		)
Other income, net	0.4			0.8			0.7			(0.1		)	1.8
(Loss) income before income taxes	(10.1		)	47.2			1.9			—			39
Income tax (provision) benefit	—			(17.8		)	(0.5		)	3.8			(14.5		)
Earnings in equity of subsidiaries	34.6			1.4			—			(36.0		)	—
Net income	$	24.5		$	30.8		$	1.4		$	(32.2	)	$	24.5
Comprehensive income	$	26.6		$	33		$	1.3		$	(34.3	)	$	26.6
CONDENSED CONSOLIDATING STATEMENT OF COMPREHESIVE INCOME
Six Months Ended June 30, 2014
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	662.8		$	67.1		$	(50.7	)	$	679.2
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			549.7			58.1			(49.4		)	558.4
Unrealized gains on derivative instruments	—			(3.6		)	—			—			(3.6		)
Depreciation and amortization	—			14.6			0.5			—			15.1
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	2.2			35.1			6.2			(1.2		)	42.3
Net periodic pension benefit income relating to VEBAs	—			(11.7		)	—			—			(11.7		)
Total selling, administrative, research and development, and general	2.2			23.4			6.2			(1.2		)	30.6
Other operating charges, net	—			0.2			—			—			0.2
Total costs and expenses	2.2			584.3			64.8			(50.6		)	600.7
Operating (loss) income	(2.2		)	78.5			2.3			(0.1		)	78.5
Other (expense) income:
Interest expense	(18.6		)	0.4			—			0.2			(18.0		)
Other income, net	1.4			2			0.5			(0.2		)	3.7
(Loss) income before income taxes	(19.4		)	80.9			2.8			(0.1		)	64.2
Income tax (provision) benefit	—			(30.4		)	(0.8		)	7.3			(23.9		)
Earnings in equity of subsidiaries	59.7			1.8			—			(61.5		)	—
Net income	$	40.3		$	52.3		$	2		$	(54.3	)	$	40.3
Comprehensive income	$	43.3		$	55.2		$	2.1		$	(57.3	)	$	43.3
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME
Quarter Ended June 30, 2013
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	324.7		$	29.6		$	(25.4	)	$	328.9
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			258.9			26.3			(23.7		)	261.5
Unrealized losses on derivative instruments	—			4.2			—			—			4.2
Depreciation and amortization	—			6.8			0.2			—			7
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	1.1			20.2			2.1			(1.6		)	21.8
Net periodic pension benefit income relating to VEBAs	—			(5.7		)	—			—			(5.7		)
Total selling, administrative, research and development, and general	1.1			14.5			2.1			(1.6		)	16.1
Total costs and expenses	1.1			284.4			28.6			(25.3		)	288.8
Operating (loss) income	(1.1		)	40.3			1			(0.1		)	40.1
Other (expense) income:
Interest expense	(9.0		)	—			—			—			(9.0		)
Other (expense) income, net	(0.9		)	0.3			(0.2		)	—			(0.8		)
(Loss) income before income taxes	(11.0		)	40.6			0.8			(0.1		)	30.3
Income tax (provision) benefit	—			(15.1		)	(0.7		)	4.1			(11.7		)
Earnings (losses) in equity of subsidiaries	29.6			(0.1		)	—			(29.5		)	—
Net income	$	18.6		$	25.4		$	0.1		$	(25.5	)	$	18.6
Comprehensive income	$	19.9		$	26.3		$	0.5		$	(26.8	)	$	19.9
CONDENSED CONSOLIDATING STATEMENT OF COMPREHESIVE INCOME
Six Months Ended June 30, 2013
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Net sales	$	—		$	656.5		$	60		$	(50.2	)	$	666.3
Costs and expenses:
Cost of products sold:
Cost of products sold, excluding depreciation and amortization and other items	—			518.6			53.3			(46.8		)	525.1
Unrealized losses on derivative instruments	—			4.9			—			—			4.9
Depreciation and amortization	—			13.5			0.5			—			14
Selling, administrative, research and development, and general
Selling, administrative, research and development, and general	1.5			40.6			4.5			(3.1		)	43.5
Net periodic pension benefit income relating to VEBAs	—			(11.3		)	—			—			(11.3		)
Total selling, administrative, research and development, and general	1.5			29.3			4.5			(3.1		)	32.2
Total costs and expenses	1.5			566.3			58.3			(49.9		)	576.2
Operating (loss) income	(1.5		)	90.2			1.7			(0.3		)	90.1
Other (expense) income:
Interest expense	(18.1		)	(0.3		)	—			0.1			(18.3		)
Other (expense) income, net	(0.5		)	0.9			(0.1		)	(0.1		)	0.2
(Loss) income before income taxes	(20.1		)	90.8			1.6			(0.3		)	72
Income tax (provision) benefit	—			(34.1		)	6.5			7.7			(19.9		)
Earnings in equity of subsidiaries	72.2			7.7			—			(79.9		)	—
Net income	$	52.1		$	64.4		$	8.1		$	(72.5	)	$	52.1
Comprehensive income	$	54.6		$	66.1		$	8.9		$	(75.0	)	$	54.6
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
Six Months Ended June 30, 2014
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Cash flows from operating activities:
Net cash provided by operating activities	$	7.6		$	56.9		$	6.8		$	—		$	71.3
Cash flows from investing activities:
Capital expenditures	—			(29.4		)	(0.7		)	—			(30.1		)
Purchase of available for sale securities	—			(23.4		)	—			—			(23.4		)
Proceeds from disposition of available for sale securities	—			25			—			—			25
Net cash used in investing activities	—			(27.8		)	(0.7		)	—			(28.5		)
Cash flows from financing activities:
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	—			0.8			—			—			0.8
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	(2.4		)	—			—			—			(2.4		)
Repurchase of common stock	(23.7		)	—			—			—			(23.7		)
Cash dividend paid to stockholders	(12.8		)	—			—			—			(12.8		)
Intercompany loan	31.3			(22.9		)	(8.4		)	—			—
Net cash used in financing activities	(7.6		)	(22.1		)	(8.4		)	—			(38.1		)
Net increase (decrease) in cash and cash equivalents during the period	—			7			(2.3		)	—			4.7
Cash and cash equivalents at beginning of period	5			157.7			6.8			—			169.5
Cash and cash equivalents at end of period	$	5		$	164.7		$	4.5		$	—		$	174.2
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
Six Months Ended June 30, 2013
	Parent			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Consolidating Adjustments			Consolidated
Cash flows from operating activities:
Net cash (used in) provided by operating activities	$	(14.4	)	$	60.4		$	2.9		$	—		$	48.9
Cash flows from investing activities:
Capital expenditures	—			(25.0		)	(1.0		)	—			(26.0		)
Purchase of available for sale securities	—			(98.2		)	—			—			(98.2		)
Proceeds from sale of available for sale securities	—			135.7			—			—			135.7
Change in restricted cash	—			0.7			—			—			0.7
Net cash provided by (used in) investing activities	—			13.2			(1.0		)	—			12.2
Cash flows from financing activities:
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	—			0.9			—			—			0.9
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	(2.2		)	—			—			—			(2.2		)
Repurchase of common stock	(39.9		)	—			—			—			(39.9		)
Cash dividend paid to stockholders	(11.6		)	—			—			—			(11.6		)
Intercompany loan	68.1			(64.8		)	(3.3		)	—			—
Net cash provided by (used in) financing activities	14.4			(63.9		)	(3.3		)	—			(52.8		)
Net increase (decrease) in cash and cash equivalents during the period	—			9.7			(1.4		)	—			8.3
Cash and cash equivalents at beginning of period	5			266			2.4			—			273.4
Cash and cash equivalents at end of period	$	5		$	275.7		$	1		$	—		$	281.7

Summary_of_Significant_Account2

Summary of Significant Accounting Policies, Textuals (Details) (USD $)	3 Months Ended	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
			Fabricated Products	Fabricated Products
Significant accounting policies	'	'	'	'
Charge decrementing prior year LIFO	$0.60	$2.40	'	'
Excess of current cost over the stated LIFO value of inventory	'	'	$17.40	$0.40

Summary_of_Significant_Account3

Summary of Significant Accounting Policies, Textuals, Property, Plant and Equipment (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Property, Plant and Equipment	'	'	'	'
Interest expense capitalized as construction in progress	$0.80	$0.70	$1.90	$1.10
Depreciation expense	'	'	14.3	13.1
Fabricated Products	'	'	'	'
Property, Plant and Equipment	'	'	'	'
Depreciation expense	$7.30	$6.50	$14.10	$13

Supplemental_Balance_Sheet_Inf2

Supplemental Balance Sheet Information (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Cash and Cash Equivalents.	'	'	'	'
Cash and money market funds	$69.70	$57.70	'	'
Commercial paper	104.5	111.8	'	'
Total	174.2	169.5	281.7	273.4
Trade Receivables.	'	'	'	'
Trade receivables, gross	123.9	120.6	'	'
Allowance for doubtful receivables	-0.8	-0.8	'	'
Trade receivables, net	123.1	119.8	'	'
Inventories.	'	'	'	'
Finished products	60.4	72.5	'	'
Work-in-process	64.3	75.9	'	'
Raw materials	53.3	47.2	'	'
Operating supplies and repair and maintenance parts	20.1	18.8	'	'
Total	198.1	214.4	'	'
Prepaid Expenses and Other Current Assets.	'	'	'	'
Current derivative assets – Notes 8 and 9	90.3	2	'	'
Current deferred tax assets	36.7	36.7	'	'
Short-term restricted cash	0.3	0.3	'	'
Prepaid taxes	1.8	0	'	'
Other	6.4	5.2	'	'
Total	135.5	44.2	'	'
Property, Plant and Equipment - Net.	'	'	'	'
Land and improvements	22.8	22.6	'	'
Buildings and leasehold improvements	54.7	53	'	'
Machinery and equipment	491.2	425.6	'	'
Construction in progress	24.7	66	'	'
Active property, plant and equipment, gross	593.4	567.2	'	'
Accumulated depreciation	-152	-137.9	'	'
Total	441.4	429.3	'	'
Other Assets.	'	'	'	'
Derivative assets – Notes 8 and 9	0.3	79.8	'	'
Restricted cash	9.3	9.3	'	'
Deferred financing costs	6.7	8.9	'	'
Deferred compensation plan assets	7.4	6.5	'	'
Other	0.3	0.3	'	'
Total	24	104.8	'	'
Other Accrued Liabilities.	'	'	'	'
Current derivative liabilities – Notes 8 and 9	89.5	1.8	'	'
Uncleared cash disbursements	9.1	9.6	'	'
Accrued income taxes and taxes payable	6.3	4.6	'	'
Accrued annual VEBA contribution	0	16	'	'
Short-term environmental accrual – Note 7	3.6	2.8	'	'
Accrued interest	3.6	3.7	'	'
Other	3	6.3	'	'
Total	115.1	44.8	'	'
Long-Term Liabilities.	'	'	'	'
Derivative liabilities – Notes 8 and 9	0.5	84.3	'	'
Income tax liabilities	5.2	5	'	'
Workers’ compensation accruals	24.4	23.3	'	'
Long-term environmental accrual – Note 7	18.6	20	'	'
Long-term asset retirement obligations	4.3	4	'	'
Deferred compensation liability	7.7	7	'	'
Long-term capital lease	0.1	0.1	'	'
Other long-term liabilities	2.9	2.7	'	'
Total	63.7	146.4	'	'
Long-Term Debt — Note 3.	'	'	'	'
Senior notes	225	225	'	'
Cash convertible senior notes	0	163.5	'	'
Total	225	388.5	'	'
Billed	'	'	'	'
Trade Receivables.	'	'	'	'
Trade receivables, gross	123.7	120.2	'	'
Unbilled	'	'	'	'
Trade Receivables.	'	'	'	'
Trade receivables, gross	$0.20	$0.40	'	'

LongTerm_Debt_and_Credit_Facil2

Long-Term Debt and Credit Facility, Textuals (Details) (USD $)

3 Months Ended

6 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

Share data in Millions, except Per Share data, unless otherwise specified

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2013

Dec. 31, 2013

Jun. 30, 2014

Jun. 30, 2014

Mar. 29, 2010

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

23-May-12

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Convertible Notes

Convertible Notes

Convertible Notes

Call Options

Warrant Transactions

Warrant Transactions

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Senior Notes

Revolving Credit Facility

Line of Credit

Letter of Credit

Minimum

Days

Long-term debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal amount of notes

$225,000,000

$225,000,000

'

$225,000,000

'

'

$175,000,000

'

'

'

'

'

'

'

$225,000,000

'

'

'

'

Interest rate

'

'

'

'

'

'

4.50%

'

'

'

'

'

'

'

8.25%

'

'

'

'

Interest expense including amortization of deferred financing costs

'

'

'

'

'

'

'

'

'

'

4,900,000

4,800,000

9,700,000

9,600,000

'

'

'

'

'

Payment of quarterly cash dividends

$0.35

$0.70

$0.60

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$0.24

Conversion rate of common stock shares per $1,000 of principal amount

'

'

'

'

'

20.8549

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal amount in conversion feature

'

'

'

'

1,000

1,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Conversion price per share of note

'

'

'

'

$47.95

$47.95

'

'

'

'

'

'

'

'

'

'

'

'

'

Threshold percentage of stock price trigger for conversion

'

'

'

'

130.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Trading days threshold for conversion

'

'

'

'

20

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Consecutive trading days threshold for conversion

'

'

'

'

'30 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Trading days warrants are exercisable

'

'120 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock sold related to option counterparties net-share-settled warrants

'

'

'

'

'

'

'

'

3.6

3.6

'

'

'

'

'

'

'

'

'

Exercise price per share of Call Options

'

'

'

'

'

'

'

$47.95

'

'

'

'

'

'

'

'

'

'

'

Exercise price per share of Warrants

'

'

'

'

'

'

'

'

60.89

61.19

'

'

'

'

'

'

'

'

'

Line of Credit Facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

300,000,000

'

'

'

Available borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

258,300,000

'

'

'

Outstanding line of credit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

-7,400,000

'

Remaining available borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$250,900,000

'

'

'

Interest on Revolving Credit Facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4.00%

'

'

'

LongTerm_Debt_and_Credit_Facil3

Long-Term Debt and Credit Facility, Carrying Amount Table (Details) (USD $)	3 Months Ended				6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Dec. 31, 2013
Principal amount, carrying amount and interest expense of notes	'		'		'		'		'
Principal amount	$225		'		$225		'		$225
Carrying amount, net of discount	0		'		0		'		163.5
Convertible Notes	'		'		'		'		'
Principal amount, carrying amount and interest expense of notes	'		'		'		'		'
Principal amount	175		'		175		'		175
Less: unamortized issuance discount	-7.1		'		-7.1		'		-11.5
Carrying amount, net of discount	167.9		'		167.9		'		163.5
Contractual coupon interest	1.9		1.9		3.9		3.9		'
Amortization of discount	2.3		2.1		4.4		4		'
Amortization of deferred financing costs	0.3		0.3		0.6		0.6		'
Total interest expense	$4.50	[1]	$4.30	[1]	$8.90	[1]	$8.50	[1]	'
[1]	A portion of the interest relating to the Convertible Notes is capitalized as Construction in progress.

Income_Tax_Matters_Provision_T

Income Tax Matters, Provision Table (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Tax Provision	'	'	'	'
Domestic	$13.90	$11.10	$23	$26.50
Foreign	0.6	0.6	0.9	-6.6
Total	$14.50	$11.70	$23.90	$19.90

Income_Tax_Matters_Textuals_De

Income Tax Matters, Textuals (Details) (USD $)	3 Months Ended			6 Months Ended		3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Sep. 30, 2013	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2013
						Canada Revenue Agency Competent Authority [Member]
Income Tax Contingency [Line Items]	'	'	'	'	'	'
Income tax provision	$14.50	'	$11.70	$23.90	$19.90	'
Effective tax rate	37.00%	'	38.60%	37.20%	27.70%	'
Unrecognized tax benefits, increase (decrease) including interest and penalties	'	'	'	'	-7.2	'
Increase (decrease) in unrecognized tax benefits, including interest and penalties	'	'	0.3	'	'	'
Increase (decrease) in effective tax rate due to unrecognized tax benefits, including interest and penalties	'	'	0.90%	'	-10.00%	'
Decrease in cash tax benefit from settlement of tax audit	'	'	'	'	'	7.7
Refund adjustment from settlement	7.2	'	'	7.2	'	'
Cash tax benefit expected to be refunded in next 12 months	'	2.8	'	'	'	'
Gross unrecognized tax benefits	3.8	'	'	3.8	'	'
Gross unrecognized tax benefits that would impact effective tax rate	2.7	'	'	2.7	'	'
Reduction in gross unrecognized tax benefits	$1.80	'	'	$1.80	'	'

Employee_Benefits_Defined_Bene

Employee Benefits, Defined Benefit Plans (Details) (USD $)

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Dec. 31, 2012

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

In Millions, unless otherwise specified

VEBAs

VEBAs

Union VEBA

Union VEBA

Union VEBA

Salaried VEBA

Variable cash contribution

Variable cash contribution

Variable cash contribution

Variable cash contribution

Variable cash contribution

Maximum

trustrees

Company Appointed

USW Appointed

VEBAs

VEBAs

VEBAs

VEBAs

VEBAs

trustrees

trustrees

Maximum

Annual Cash Flows up to $20 Million

Annual Cash Flows in Excess of $20 Million

VEBA Postretirement Medical Obligations

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of trustees

'

'

'

'

4

2

2

'

'

'

'

'

'

Administrative expenses of the VEBAs

'

'

'

$0.30

'

'

'

'

'

'

'

'

'

Postretirement medical plan contribution obligation percentage

'

'

'

'

'

'

'

'

'

'

'

10.00%

20.00%

Cash flow in determining VEBA obligation

'

'

20

'

'

'

'

'

'

'

'

'

'

Variable cash contribution obligation to VEBAs

'

'

'

'

'

'

'

'

'

'

20

'

'

Percent allocation of total contribution between VEBAs

'

'

'

'

85.50%

'

'

14.50%

'

'

'

'

'

Annual variable cash contribution

$0

$16

'

'

'

'

'

'

$16

$20

'

'

'

Employee_Benefits_Net_Periodic

Employee Benefits, Net Periodic Benefit Costs and Charges Relating To All Other Employee Benefit Plans(Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
VEBAs:	'	'	'	'
Total net periodic pension benefit (income) expense relating to VEBAs	($6.10)	($5.70)	($11.70)	($11.30)
Deferred compensation plan	0.4	0	0.6	0.4
Defined contribution plans	1.5	1.3	5.5	5.3
Multiemployer pension plans	0.9	0.9	1.8	1.7
Total	-3.3	-3.5	-3.8	-3.9
Fabricated Products	'	'	'	'
VEBAs:	'	'	'	'
Total	2.3	2	6.9	6.6
All Other	'	'	'	'
VEBAs:	'	'	'	'
Total	-5.6	-5.5	-10.7	-10.5
VEBAs	'	'	'	'
VEBAs:	'	'	'	'
Service cost	0.5	0.7	1.1	1.3
Interest cost	4.2	3.7	8.3	7.3
Expected return on plan assets	-12.8	-11.5	-25.6	-22.7
Amortization of prior service cost	2.6	1	5.4	2.1
Amortization of net actuarial (gain) loss	-0.6	0.4	-0.9	0.7
Total net periodic pension benefit (income) expense relating to VEBAs	($6.10)	($5.70)	($11.70)	($11.30)

Employee_Incentive_Plans_Short

Employee Incentive Plans, Short Term Incentive Plans (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
EVA measurement period	'	'	'1 year	'
Compensation charges associated with STI Plans	'	'	'	'
Costs recorded in connection with STI plans	$4.60	$4.80	$7	$8.90
Fabricated Products	'	'	'	'
Compensation charges associated with STI Plans	'	'	'	'
Costs recorded in connection with STI plans	3.5	3.3	5.4	6.2
All Other	'	'	'	'
Compensation charges associated with STI Plans	'	'	'	'
Costs recorded in connection with STI plans	1.1	1.5	1.6	2.7
Cost of products sold, excluding depreciation and amortization and other items	'	'	'	'
Compensation charges associated with STI Plans	'	'	'	'
Costs recorded in connection with STI plans	1.4	1.3	2.5	2.4
Selling, administrative, research and development, and general	'	'	'	'
Compensation charges associated with STI Plans	'	'	'	'
Costs recorded in connection with STI plans	$3.20	$3.50	$4.50	$6.50

Employee_Incentive_Plans_Long_

Employee Incentive Plans, Long term Incentive Plans (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Number of common shares authorized for issuance under Equity Incentive Plan	2,722,222	'	2,722,222	'	'
Number of common shares available for additional awards under Equity Incentive Plan	698,231	'	698,231	'	'
Non-cash compensation expense	$2.30	$1.90	$4.30	$4.50	'
Stock Options	'	'	'	'	'
Fully-vested options outstanding	20,791	'	20,791	'	20,791
Exercise price of options to purchase common stock	$80.01	'	$80.01	'	$80.01
Remaining contractual life of options outstanding	'	'	'2 years 9 months	'	'3 years 3 months
Grant date fair value of options outstanding	'	'	$39.90	'	$39.90
Stock options granted	'	'	0	'	'
Stock options forfeited	'	'	0	'	'
Stock options exercised	'	'	0	'	'
Vested Stock	'	'	'	'	'
Issuance of common shares to non-employee directors	'	'	0.2	0.2	'
Common shares withheld and canceled	'	'	33,006	36,221	'
Fabricated Products	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Non-cash compensation expense	1.1	0.6	2.1	1.2	'
All Other	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Non-cash compensation expense	1.2	1.3	2.2	3.3	'
Non-vested common shares	'	'	'	'	'
Summary of Activity	'	'	'	'	'
Outstanding at December 31, 2013, Shares	'	'	143,967	'	'
Outstanding at December 31, 2013, Weighted-Average Grant-Date Fair Value per Share	'	'	$51.09	'	'
Granted, shares	'	'	118,638	74,236	'
Granted, Weighted-Average Grant-Date Fair Value per Share	'	'	$66.31	$58.49	'
Vested, shares	'	'	-62,659	-81,161	'
Vested, Weighted-Average Grant-Date Fair Value per Share	'	'	$52.43	$41.67	'
Forfeited, shares	'	'	-526	'	'
Forfeited, Weighted-Average Grant-Date Fair Value per Share	'	'	$55.03	'	'
Canceled, Shares	'	'	0	'	'
Canceled, Weighted-Average Grant-Date Fair Value per Share	'	'	$0	'	'
Outstanding at June 30, 2014, Shares	199,420	'	199,420	'	'
Outstanding at June 30, 2014, Weighted-Average Grant-Date Fair Value per Share	$59.71	'	$59.71	'	'
Restricted stock units (RSUs)	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Number of common shares received by the employee on vesting of restricted stock unit	'	'	1	'	'
Summary of Activity	'	'	'	'	'
Outstanding at December 31, 2013, Shares	'	'	5,472	'	'
Outstanding at December 31, 2013, Weighted-Average Grant-Date Fair Value per Share	'	'	$51.03	'	'
Granted, shares	'	'	2,235	2,600	'
Granted, Weighted-Average Grant-Date Fair Value per Share	'	'	$67.42	$57.70	'
Vested, shares	'	'	-2,350	-2,311	'
Vested, Weighted-Average Grant-Date Fair Value per Share	'	'	$46.83	$42.74	'
Forfeited, shares	'	'	0	'	'
Forfeited, Weighted-Average Grant-Date Fair Value per Share	'	'	$0	'	'
Canceled, Shares	'	'	0	'	'
Canceled, Weighted-Average Grant-Date Fair Value per Share	'	'	$0	'	'
Outstanding at June 30, 2014, Shares	5,357	'	5,357	'	'
Outstanding at June 30, 2014, Weighted-Average Grant-Date Fair Value per Share	$59.71	'	$59.71	'	'
Service-based non-vested common shares and restricted stock units	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Non-cash compensation expense	1.2	0.8	2.3	2.5	'
Unrecognized gross compensation costs, by award type	9.5	'	9.5	'	'
Expected period (in years) over which the remaining gross compensation costs will be recognized, by award type	'	'	'2 years 10 months 24 days	'	'
Performance shares	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Performance award vesting period, years	'	'	'3 years	'	'
Non-cash compensation expense	0.5	1.1	1	2	'
Unrecognized gross compensation costs, by award type	3	'	3	'	'
Expected period (in years) over which the remaining gross compensation costs will be recognized, by award type	'	'	'1 year 6 months	'	'
Summary of Activity	'	'	'	'	'
Outstanding at December 31, 2013, Shares	'	'	562,554	'	'
Outstanding at December 31, 2013, Weighted-Average Grant-Date Fair Value per Share	'	'	$49.26	'	'
Granted, shares	'	'	0	170,298	'
Granted, Weighted-Average Grant-Date Fair Value per Share	'	'	$0	$57.57	'
Vested, shares	'	'	-42,545	-32,312	'
Vested, Weighted-Average Grant-Date Fair Value per Share	'	'	$47.04	$34.13	'
Forfeited, shares	'	'	-1,682	'	'
Forfeited, Weighted-Average Grant-Date Fair Value per Share	'	'	$50.40	'	'
Canceled, Shares	'	'	-139,384	'	'
Canceled, Weighted-Average Grant-Date Fair Value per Share	'	'	$46.77	'	'
Outstanding at June 30, 2014, Shares	378,943	'	378,943	'	'
Outstanding at June 30, 2014, Weighted-Average Grant-Date Fair Value per Share	$50.43	'	$50.43	'	'
Market-based shares	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Non-cash compensation expense	0.6	0	1	0	'
Unrecognized gross compensation costs, by award type	$5.70	'	$5.70	'	'
Expected period (in years) over which the remaining gross compensation costs will be recognized, by award type	'	'	'2 years 7 months 6 days	'	'
Summary of Activity	'	'	'	'	'
Outstanding at December 31, 2013, Shares	'	'	0	'	'
Outstanding at December 31, 2013, Weighted-Average Grant-Date Fair Value per Share	'	'	$0	'	'
Granted, shares	'	'	160,868	'	'
Granted, Weighted-Average Grant-Date Fair Value per Share	'	'	$83.18	'	'
Vested, shares	'	'	0	'	'
Vested, Weighted-Average Grant-Date Fair Value per Share	'	'	$0	'	'
Forfeited, shares	'	'	-235	'	'
Forfeited, Weighted-Average Grant-Date Fair Value per Share	'	'	$83.18	'	'
Canceled, Shares	'	'	0	'	'
Canceled, Weighted-Average Grant-Date Fair Value per Share	'	'	$0	'	'
Outstanding at June 30, 2014, Shares	160,633	'	160,633	'	'
Outstanding at June 30, 2014, Weighted-Average Grant-Date Fair Value per Share	$83.18	'	$83.18	'	'

Commitments_and_Contingencies_

Commitments and Contingencies, Textuals (Details) (USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Environmental Contingency	'
Environmental accrual	$22.20
Expected period related to remediation expenditures for environmental contingencies period	'30 years
Potential increase in environmental costs	$24.90
Minimum	'
Environmental Contingency	'
Period for final feasibility study	'18 months
Maximum	'
Environmental Contingency	'
Period for final feasibility study	'24 months

Derivative_Financial_Instrumen2

Derivative Financial Instruments and Related Hedging Programs, Hedging Discussion (Details) (USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014	Jun. 30, 2014	Mar. 29, 2010
	mmlbs	mmlbs		Remainder of 2014	2015	Convertible Notes
				mmlbs	mmlbs
Derivative Financial Instruments and Related Hedging Programs (Textuals) [Abstract]	'	'	'	'	'	'
Aggregate fair value of derivative instruments that contain credit-risk-related contingency features that were in a net liability position	$0.20	'	$1.60	'	'	'
Total fabricated products shipments containing fixed price terms	68.5	58.2	'	'	'	'
Firm price customer sales contracts containing price risk on anticipated purchases of primary aluminum	'	'	'	49.3	4.3	'
Principal amount of notes	$225	'	$225	'	'	$175

Derivative_Financial_Instrumen3

Derivative Financial Instruments and Related Hedging Programs, Realized and Unrealized Gains (Losses) Table (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Unrealized gains (losses)	'	'	$4.90	($5.40)
Not Designated as Hedging Instrument	'	'	'	'
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Realized (losses) gains	1.3	-1.8	3.3	-2.5
Unrealized gains (losses)	2	-5.1	4.9	-5.4
Aluminum | Not Designated as Hedging Instrument	'	'	'	'
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Realized (losses) gains	1.3	-1.6	2.1	-1.6
Unrealized gains (losses)	0.6	-1.8	2.3	-6.2
Natural Gas | Not Designated as Hedging Instrument	'	'	'	'
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Realized (losses) gains	0.5	-0.1	1.2	-0.8
Unrealized gains (losses)	-0.2	-1.9	0.6	0.8
Electricity | Not Designated as Hedging Instrument	'	'	'	'
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Realized (losses) gains	-0.5	-0.1	0	-0.1
Unrealized gains (losses)	1.2	-0.6	0.7	0.6
Foreign Currency | Not Designated as Hedging Instrument	'	'	'	'
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Unrealized gains (losses)	-0.1	0.1	-0.1	-0.1
Hedges Relating to the Convertible Notes | Call Options | Not Designated as Hedging Instrument	'	'	'	'
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Unrealized gains (losses)	2.5	-9.1	6.9	-3.1
Hedges Relating to the Convertible Notes | Bifurcated Conversion Feature | Not Designated as Hedging Instrument	'	'	'	'
Summary Of Realized And Unrealized Gains (Losses)	'	'	'	'
Unrealized gains (losses)	($2)	$8.20	($5.50)	$2.60

Derivative_Financial_Instrumen4

Derivative Financial Instruments and Related Hedging Programs, Notional Quantity Table (Details)	Jun. 30, 2014
Remainder of 2014	'
Summary of material derivative positions	'
Percentage of natural gas purchases for which the Company's exposure to fluctuations in gas prices had been substantially reduced	88.00%
2015	'
Summary of material derivative positions	'
Percentage of natural gas purchases for which the Company's exposure to fluctuations in gas prices had been substantially reduced	82.00%
2016	'
Summary of material derivative positions	'
Percentage of natural gas purchases for which the Company's exposure to fluctuations in gas prices had been substantially reduced	30.00%
Not Designated as Hedging Instrument | Aluminum | Fixed priced contracts | Purchase	'
Summary of material derivative positions	'
Notional amount of contracts	44.1
Not Designated as Hedging Instrument | Aluminum | Fixed priced contracts | Sales	'
Summary of material derivative positions	'
Notional amount of contracts	1.3
Not Designated as Hedging Instrument | Aluminum | Midwest premium swap contracts | Purchase	'
Summary of material derivative positions	'
Notional amount of contracts	42.3	[1]
Not Designated as Hedging Instrument | Natural Gas | Fixed priced contracts | Purchase	'
Summary of material derivative positions	'
Notional amount of contracts	6,150,000	[2]
Not Designated as Hedging Instrument | Electricity | Fixed priced contracts | Purchase	'
Summary of material derivative positions	'
Notional amount of contracts	285,625
Not Designated as Hedging Instrument | Hedges Relating to the Convertible Notes | Bifurcated Conversion Feature	'
Summary of material derivative positions	'
Notional amount of contracts	3,649,608	[3]
Not Designated as Hedging Instrument | Hedges Relating to the Convertible Notes | Call Options	'
Summary of material derivative positions	'
Notional amount of contracts	3,649,608	[3]
[1]	Regional premiums represent the premium over the London Metal Exchange price for primary aluminum which is incurred on the Company’s purchases of primary aluminum.
[2]	As of June 30, 2014, the Company’s exposure to fluctuations in natural gas prices had been substantially reduced for approximately 88%, 82% and 30% of the expected natural gas purchases for the remainder of 2014, 2015 and 2016, respectively.
[3]	The Bifurcated Conversion Feature represents the cash conversion feature of the Convertible Notes. The Call Options expire on the maturity or earlier conversion of the Convertible Notes and have an exercise price equal to the conversion price of the Convertible Notes, subject to anti-dilution adjustments substantially similar to the anti-dilution adjustments for the Convertible Notes. Although the fair value of the Call Options is derived from a notional number of shares of the Company’s common stock, the Call Options may only be settled in cash.

Derivative_Financial_Instrumen5

Derivative Financial Instruments and Related Hedging Programs, Offsetting of Derivative Instruments by Counterparty (Details) (USD $)	Jun. 30, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Derivative Assets and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Assets	$90.60		$81.80
Gross Amounts Offset in the Consolidated Balance Sheets	0		0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	90.6		81.8
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	1.1		1.2
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0		0
Net Amount	89.5		80.6
Derivative Liabilities and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Liabilities	-90		-86.1
Gross Amounts Offset in the Consolidated Balance Sheets	0		0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	-90		-86.1
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	-1.1		-1.2
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0		0
Net Amount	-88.9		-84.9
Counterparty (with Netting Agreements)	'		'
Derivative Assets and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Assets	2		1
Gross Amounts Offset in the Consolidated Balance Sheets	0		0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	2		1
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0.8		0.8
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0		0
Net Amount	1.2		0.2
Derivative Liabilities and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Liabilities	-0.8		-1.6
Gross Amounts Offset in the Consolidated Balance Sheets	0		0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	-0.8		-1.6
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	-0.8		-0.8
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0		0
Net Amount	0		-0.8
Counterparty (without Netting Agreements)	'		'
Derivative Assets and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Assets	87.6	[1]	80.4	[1]
Gross Amounts Offset in the Consolidated Balance Sheets	0	[1]	0	[1]
Net Amounts of Assets Presented in the Consolidated Balance Sheets	87.6	[1]	80.4	[1]
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0	[1]	0	[1]
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0	[1]	0	[1]
Net Amount	87.6	[1]	80.4	[1]
Derivative Liabilities and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Liabilities	-88.7	[1]	-83.2	[1]
Gross Amounts Offset in the Consolidated Balance Sheets	0	[1]	0	[1]
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	-88.7	[1]	-83.2	[1]
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0	[1]	0	[1]
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0	[1]	0	[1]
Net Amount	-88.7	[1]	-83.2	[1]
Counterparty (with partial Netting Agreements)	'		'
Derivative Assets and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Assets	1		0.4
Gross Amounts Offset in the Consolidated Balance Sheets	0		0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	1		0.4
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0.3		0.4
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0		0
Net Amount	0.7		0
Derivative Liabilities and Collateral Held by Counterparty	'		'
Gross Amounts of Recognized Liabilities	-0.5		-1.3
Gross Amounts Offset in the Consolidated Balance Sheets	0		0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	-0.5		-1.3
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	-0.3		-0.4
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0		0
Net Amount	($0.20)		($0.90)
[1]	Such amounts include the fair value of the Bifurcated Conversion Feature and Call Options at June 30, 2014 (see Note 9).

Fair_Value_Measurements_Call_O

Fair Value Measurements, Call Option FV Assumption Table (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014		Jun. 30, 2014		Jun. 30, 2013
	basispoints		basispoints
Fair Value Disclosures [Abstract]	'		'		'
The Company’s stock price at June 30, 2014	$72.87		$72.87		'
Quarterly dividend yield (per share) upon purchase of the Call Option	$0.24	[1]	'		'
Risk-free interest rate	'		0.08%	[2]	'
Credit spread (basis points)	130	[3]	130	[3]	'
Expected volatility rate	'		17.00%	[4]	'
Cash dividends paid per share	$0.35		$0.70		$0.60
Six-month Constant Maturity Treasury rate	'		'6 months		'
One-year Constant Maturity Treasury rate	'		'1 year		'
[1]	The quarterly dividend in the second quarter of 2014 was $0.35 per share, but the model assumes a $0.24 per share quarterly dividend as was paid at the inception of the Call Options. Quarterly dividends in excess of $0.24 per share do not affect the Call Options’ value due to anti-dilution adjustments.
[2]	The risk-free rate was based on the six-month Constant Maturity Treasury rate and one-year Constant Maturity Treasury rate on June 30, 2014.
[3]	The credit spread is based on the Company’s long-term credit rating of BB issued by Standard & Poor’s.
[4]	The volatility rate was based on both observed volatility, which is based on the Company’s historical stock price, and implied volatility from the Company’s traded options. Such volatility was further adjusted to take into consideration market participant risk tolerance.

Fair_Value_Measurements_Fair_V

Fair Value Measurements Fair Value Measurements, Textual (Details) (USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
			Minimum	Maximum	Derivative	Derivative
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'	'	'
Fair Value, Net Asset (Liability)	'	'	'	'	$0.60	($4.30)
Non-cash unrealized (gains) losses on derivative positions	$4.90	($5.40)	'	'	'	'
Short-term investment maturity period	'	'	'32 days	'9 months	'	'

Fair_Value_Measurements_Fair_V1

Fair Value Measurements, Fair Value Hierarchy Table (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Financial Assets:	'	'
Derivative Assets	$90.60	$81.80
Deferred compensation plan assets	7.4	6.5
Financial Liabilities:	'	'
Derivative Liabilities	-90	-86.1
Recurring	'	'
Financial Assets:	'	'
Cash and cash equivalents	174.2	169.5
Deferred compensation plan assets	7.4	6.5
Total Assets	399.4	387.3
Financial Liabilities:	'	'
Convertible Notes	-269.7	-260
Total Liabilities	-612.9	-601.5
Recurring | Senior Notes	'	'
Financial Liabilities:	'	'
Senior Notes	-253.2	-255.4
Recurring | Debt securities	'	'
Financial Assets:	'	'
Short-term investments	127.2	129.5
Recurring | Aluminum | Midwest premium swap contracts	'	'
Financial Assets:	'	'
Derivative Assets	1.4	1.1
Recurring | Aluminum | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0.8	0.1
Financial Liabilities:	'	'
Derivative Liabilities	-0.5	-1.8
Recurring | Natural Gas | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0.9	0.5
Financial Liabilities:	'	'
Derivative Liabilities	-0.6	-0.8
Recurring | Electricity | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	1	0.5
Financial Liabilities:	'	'
Derivative Liabilities	-0.2	-0.4
Recurring | Foreign Currency | Fixed priced contracts | Purchase | Euro	'	'
Financial Assets:	'	'
Derivative Assets	'	0.1
Recurring | Hedges Relating to the Convertible Notes | Call Options	'	'
Financial Assets:	'	'
Derivative Assets	86.5	79.5
Recurring | Hedges Relating to the Convertible Notes | Bifurcated Conversion Feature	'	'
Financial Liabilities:	'	'
Derivative Liabilities	-88.7	-83.1
Recurring | Level 1	'	'
Financial Assets:	'	'
Cash and cash equivalents	69.7	57.7
Deferred compensation plan assets	0	0
Total Assets	69.7	57.7
Financial Liabilities:	'	'
Convertible Notes	-269.7	-260
Total Liabilities	-522.9	-515.4
Recurring | Level 1 | Senior Notes	'	'
Financial Liabilities:	'	'
Senior Notes	-253.2	-255.4
Recurring | Level 1 | Debt securities	'	'
Financial Assets:	'	'
Short-term investments	0	0
Recurring | Level 1 | Aluminum | Midwest premium swap contracts	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Recurring | Level 1 | Aluminum | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Financial Liabilities:	'	'
Derivative Liabilities	0	0
Recurring | Level 1 | Natural Gas | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Financial Liabilities:	'	'
Derivative Liabilities	0	0
Recurring | Level 1 | Electricity | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Financial Liabilities:	'	'
Derivative Liabilities	0	0
Recurring | Level 1 | Foreign Currency | Fixed priced contracts | Purchase | Euro	'	'
Financial Assets:	'	'
Derivative Assets	'	0
Recurring | Level 1 | Hedges Relating to the Convertible Notes | Call Options	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Recurring | Level 1 | Hedges Relating to the Convertible Notes | Bifurcated Conversion Feature	'	'
Financial Liabilities:	'	'
Derivative Liabilities	0	0
Recurring | Level 2	'	'
Financial Assets:	'	'
Cash and cash equivalents	104.5	111.8
Deferred compensation plan assets	7.4	6.5
Total Assets	328.3	328.5
Financial Liabilities:	'	'
Convertible Notes	0	0
Total Liabilities	-90	-86.1
Recurring | Level 2 | Senior Notes	'	'
Financial Liabilities:	'	'
Senior Notes	0	0
Recurring | Level 2 | Debt securities	'	'
Financial Assets:	'	'
Short-term investments	127.2	129.5
Recurring | Level 2 | Aluminum | Midwest premium swap contracts	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Recurring | Level 2 | Aluminum | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0.8	0.1
Financial Liabilities:	'	'
Derivative Liabilities	-0.5	-1.8
Recurring | Level 2 | Natural Gas | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0.9	0.5
Financial Liabilities:	'	'
Derivative Liabilities	-0.6	-0.8
Recurring | Level 2 | Electricity | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	1	0.5
Financial Liabilities:	'	'
Derivative Liabilities	-0.2	-0.4
Recurring | Level 2 | Foreign Currency | Fixed priced contracts | Purchase | Euro	'	'
Financial Assets:	'	'
Derivative Assets	'	0.1
Recurring | Level 2 | Hedges Relating to the Convertible Notes | Call Options	'	'
Financial Assets:	'	'
Derivative Assets	86.5	79.5
Recurring | Level 2 | Hedges Relating to the Convertible Notes | Bifurcated Conversion Feature	'	'
Financial Liabilities:	'	'
Derivative Liabilities	-88.7	-83.1
Recurring | Level 3	'	'
Financial Assets:	'	'
Cash and cash equivalents	0	0
Deferred compensation plan assets	0	0
Total Assets	1.4	1.1
Financial Liabilities:	'	'
Convertible Notes	0	0
Total Liabilities	0	0
Recurring | Level 3 | Senior Notes	'	'
Financial Liabilities:	'	'
Senior Notes	0	0
Recurring | Level 3 | Debt securities	'	'
Financial Assets:	'	'
Short-term investments	0	0
Recurring | Level 3 | Aluminum | Midwest premium swap contracts	'	'
Financial Assets:	'	'
Derivative Assets	1.4	1.1
Recurring | Level 3 | Aluminum | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Financial Liabilities:	'	'
Derivative Liabilities	0	0
Recurring | Level 3 | Natural Gas | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Financial Liabilities:	'	'
Derivative Liabilities	0	0
Recurring | Level 3 | Electricity | Fixed priced contracts | Purchase	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Financial Liabilities:	'	'
Derivative Liabilities	0	0
Recurring | Level 3 | Foreign Currency | Fixed priced contracts | Purchase | Euro	'	'
Financial Assets:	'	'
Derivative Assets	'	0
Recurring | Level 3 | Hedges Relating to the Convertible Notes | Call Options	'	'
Financial Assets:	'	'
Derivative Assets	0	0
Recurring | Level 3 | Hedges Relating to the Convertible Notes | Bifurcated Conversion Feature	'	'
Financial Liabilities:	'	'
Derivative Liabilities	$0	$0

Fair_Value_Measurements_Level_

Fair Value Measurements, Level 3 Fair Value Input Reconciliation Table (Details) (Derivative, Midwest premium swap contracts, USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014
Derivative | Midwest premium swap contracts	'
Reconciliation of activity for financial instruments classified as Level 3:	'
Balance at December 31, 2013	$1.10
Total realized/unrealized gains included in:	'
Cost of goods sold excluding depreciation and amortization and other items and Unrealized (gains) losses on derivative instruments	4.1
Transactions involving Level 3 derivative contracts:	'
Purchases	0.6
Sales	0
Issuances	0
Settlements	-4.4
Transactions involving Level 3 derivatives — net	-3.8
Transfers in and (or) out of Level 3 valuation hierarchy	0
Balance at June 30, 2014	1.4
Total gains included in Unrealized (gains) losses on derivative instruments, attributable to the change in unrealized gains/losses relating to derivative contracts held at June 30, 2014:	$1.10

Earnings_Per_Share_Calculation

Earnings Per Share, Calculation of EPS (Details) (USD $)	3 Months Ended				6 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Numerator:	'		'		'		'
Net income	$24.50		$18.60		$40.30		$52.10
Denominator — Weighted-average common shares outstanding (in thousands):	'		'		'		'
Basic	17,841	[1]	18,742	[1]	17,889	[1]	19,027	[1]
Add: dilutive effect of non-vested common shares, restricted stock units and performance shares	112		112		133		135
Add: dilutive effect of warrants	505		91		490		94
Diluted	18,458	[2]	18,945	[2]	18,512	[2]	19,256	[2]
Earnings per common share, Basic:	'		'		'		'
Net income per share	$1.38		$0.99		$2.25		$2.73
Earnings per common share, Diluted:	'		'		'		'
Net income per share	$1.33		$0.98		$2.18		$2.70
[1]	The basic weighted-average number of common shares outstanding during the period excludes non-vested common shares, restricted stock units, performance shares and market-based shares.
[2]	The diluted weighted-average number of common shares outstanding during the periods were calculated using the treasury method.

Earnings_Per_Share_Textuals_De

Earnings Per Share, Textuals (Details) (USD $)	3 Months Ended	6 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Potential dilutive effect of options and Warrants	'	'	'	'
Options outstanding to purchase common shares	20,791	20,791	'	20,791
Average exercise price per share	$80.01	$80.01	'	$80.01
Dividends	'	'	'	'
Cash dividends paid	'	$12.80	$11.60	'
Cash dividends paid per share	$0.35	$0.70	$0.60	'
Treasury Stock, Number of Shares and Restriction Disclosures [Abstract]	'	'	'	'
Repurchase of common stock	'	346,781	654,277	'
Weighted-average price per share of common stock repurchased	'	$69.25	$61.95	'
Repurchase of common stock, total cost	'	24	40.5	'
Common share amount available for additional share repurchase	'	$93.60	'	$117.60
Warrant Transactions	'	'	'	'
Potential dilutive effect of options and Warrants	'	'	'	'
Number of common shares underlying the Warrants outstanding	3,600,000	3,600,000	3,600,000	'
Average exercise price of common shares underlying Warrants	60.89	60.89	61.19	'

Segment_Information_Textuals_D

Segment Information, Textuals (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]	'	'	'	'
Charge decrementing prior year LIFO	$0.60	'	$2.40	'
Unrealized gains (losses) on derivatives	'	'	4.9	-5.4
VEBA net periodic pension benefit income	6.1	5.7	11.7	11.3
Fabricated Products	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Unrealized gains (losses) on derivatives	1.5	-4.2	3.5	-4.9
United States	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Number of production facilities	'	'	11	'
Canada	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
Number of production facilities	'	'	1	'
VEBAs	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'
VEBA net periodic pension benefit income	$6.10	$5.70	$11.70	$11.30

Segment_Information_Financial_

Segment Information, Financial Information by Reporting Segment Table (Details) (USD $)	3 Months Ended				6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013		Dec. 31, 2013
Net sales:	'		'		'		'		'
Net Sales	$344.10		$328.90		$679.20		$666.30		'
Segment operating income (loss):	'		'		'		'		'
Operating income (loss)	46.4		40.1		78.5		90.1		'
Interest expense	-9.2		-9		-18		-18.3		'
Other income, net	1.8		-0.8		3.7		0.2		'
Income before income taxes	39		30.3		64.2		72		'
Depreciation and amortization:	'		'		'		'		'
Depreciation and amortization	7.7		7		15.1		14		'
Capital expenditures:	'		'		'		'		'
Capital expenditures	14.7		16.7		30.1		26		'
Income taxes paid:	'		'		'		'		'
Income taxes paid	0.4		0.6		1.1		1.3		'
Assets:	'		'		'		'		'
Assets	1,772.60		'		1,772.60		'		1,770.90
Fabricated Products	'		'		'		'		'
Net sales:	'		'		'		'		'
Net Sales	344.1		328.9		679.2		666.3		'
Segment operating income (loss):	'		'		'		'		'
Operating income (loss)	50.2	[1],[2]	45	[1],[2]	85.6	[1],[2]	100.2	[1],[2]	'
Depreciation and amortization:	'		'		'		'		'
Depreciation and amortization	7.7		6.9		14.9		13.8		'
Capital expenditures:	'		'		'		'		'
Capital expenditures	14.2		16.5		29.5		25.4		'
Assets:	'		'		'		'		'
Assets	851.4		'		851.4		'		852.5
Fabricated Products | United States	'		'		'		'		'
Income taxes paid:	'		'		'		'		'
Income taxes paid	0.1		0.3		0.2		0.6		'
Fabricated Products | Canada	'		'		'		'		'
Income taxes paid:	'		'		'		'		'
Income taxes paid	0.3		0.3		0.9		0.7		'
All Other	'		'		'		'		'
Segment operating income (loss):	'		'		'		'		'
Operating income (loss)	-3.8	[3]	-4.9	[3]	-7.1	[3]	-10.1	[3]	'
Depreciation and amortization:	'		'		'		'		'
Depreciation and amortization	0		0.1		0.2		0.2		'
Capital expenditures:	'		'		'		'		'
Capital expenditures	0.5		0.2		0.6		0.6		'
Assets:	'		'		'		'		'
Assets	$921.20	[4]	'		$921.20	[4]	'		$918.40	[4]
[1]	Operating results in the Fabricated Products segment for the quarter ended June 30, 2014 included a charge of $0.6 as a result of decrementing a prior year, higher cost LIFO layer. Operating results in the Fabricated Products segment for the six months ended June 30, 2014 included a charge of $2.4 as a result of decrementing a prior year, higher cost layer.
[2]	Fabricated Products segment operating income included non-cash mark-to-market gains (losses) on primary aluminum, natural gas, electricity and foreign currency hedging activities totaling $1.5 and $(4.2) for the quarters ended June 30, 2014 and June 30, 2013, respectively. Non-cash mark-to-market gains (losses) on primary aluminum, natural gas, electricity and foreign currency hedging activities totaled $3.5 and $(4.9) for the six months ended June 30, 2014 and June 30, 2013, respectively. For further discussion regarding mark-to-market matters, see Note 8.
[3]	Operating loss in All Other included VEBA net periodic pension benefit income of $6.1 and $5.7 for the quarters ended June 30, 2014 and June 30, 2013, respectively. VEBA net periodic pension benefit income was $11.7 and $11.3 for the six months ended June 30, 2014 and June 30, 2013, respectively.
[4]	Assets in All Other represent primarily all of the Company’s cash and cash equivalents, short-term investments, financial derivative assets, net assets in respect of VEBA(s) (see Note 5) and net deferred income tax assets.

Segment_Information_Net_Sales_

Segment Information, Net Sales by Product Categories (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net Sales:	'	'	'	'
Net sales	$344.10	$328.90	$679.20	$666.30
Aero/HS products	'	'	'	'
Net Sales:	'	'	'	'
Net sales	173	165.1	336.6	344.7
GE products	'	'	'	'
Net Sales:	'	'	'	'
Net sales	107.3	110.2	219.5	216
Automotive Extrusions	'	'	'	'
Net Sales:	'	'	'	'
Net sales	44.7	31	85.5	61.8
Other products	'	'	'	'
Net Sales:	'	'	'	'
Net sales	$19.10	$22.60	$37.60	$43.80

Supplemental_Cash_Flow_Informa2

Supplemental Cash Flow Information (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Supplemental disclosure of cash flow information:	'	'	'	'
Interest paid	'	'	$12.10	$14
Income taxes paid	0.4	0.6	1.1	1.3
Supplemental disclosure of non-cash transactions:	'	'	'	'
Stock repurchases not yet settled (accrued in accounts payable)	'	'	0.3	0.6
Non-cash capital expenditures	'	'	1.1	4.4
Capital leases acquired	'	'	$0	$0.20

Other_Income_Expense_Net_Detai

Other Income (Expense), Net (Details) (USD $)	3 Months Ended				6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Other Income and Expenses [Abstract]	'		'		'		'
Interest income	$0.20		$0		$0.50		$0.10
Unrealized gains (losses) on financial derivatives	0.5	[1]	-0.9	[1]	1.4	[1]	-0.5	[1]
Realized gains on investments	0.2		0.3		0.4		0.8
All other, net	0.9		-0.2		1.4		-0.2
Other non-operating income (expense), net	$1.80		($0.80)		$3.70		$0.20
[1]	See “Hedges Relating to the Convertible Notes” in Note 8 for discussion of such instruments.

Other_Comprehensive_Income_Det

Other Comprehensive Income (Details) (USD $)	3 Months Ended				6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Reclassification adjustments, before tax:	'		'		'		'
Amortization of net actuarial (gain) loss, before tax	($0.60)	[1]	$0.40	[1]	($0.90)	[1]	$0.70	[1]
Amortization of prior service cost, before tax	2.6	[1]	1	[1]	5.4	[1]	2.1	[1]
Other comprehensive income relating to VEBAs, before tax	2		1.4		4.5		2.8
Available for sale securities:	'		'		'		'
Unrealized gain on available for sale securities, before tax	0.2		0.2		0.3		0.5
Reclassification adjustments, before tax:	'		'		'		'
Reclassification of unrealized gain upon sale of available for sale securities, before tax	-0.1	[2]	-0.2	[2]	-0.2	[2]	-0.6	[2]
Other comprehensive income (loss) relating to available for sale securities, before tax	0.1		0		0.1		-0.1
Foreign currency translation adjustment, before tax	-0.1		0.4		0.1		0.8
Cumulative tax rate adjustment, before tax	0		'		'		'
Other comprehensive income, before tax	2		1.8		4.7		3.5
Reclassification adjustments, income tax (expense) benefit:	'		'		'		'
Amortization of net actuarial (gain) loss, income tax (expense) benefit	0.2	[1],[3]	-0.1	[1],[3]	0.3	[1],[3]	-0.2	[1],[3]
Amortization of prior service cost, income tax (expense) benefit	-1	[1],[3]	-0.4	[1],[3]	-2	[1],[3]	-0.8	[1],[3]
Other comprehensive income relating to VEBAs, income tax (expense) benefit	-0.8	[3]	-0.5	[3]	-1.7	[3]	-1	[3]
Available for sale securities:	'		'		'		'
Unrealized gain on available for sale securities, Income tax (expense) benefit	-0.1	[3]	-0.1		-0.1	[3]	-0.2	[3]
Reclassification adjustments, income tax (expense) benefit:	'		'		'		'
Reclassification of unrealized gain upon sale of available for sale securities, income tax (expense) benefit	0.1	[2],[3]	0.1	[2],[3]	0.1	[2],[3]	0.2	[2],[3]
Other comprehensive income (loss) relating to available for sale securities, income tax (expense) benefit	0	[3]	0	[3]	0	[3]	0	[3]
Foreign currency translation adjustment, income tax (expense) benefit	0	[3]	0	[3]	0	[3]	0	[3]
Cumulative tax rate adjustment, tax	0.9	[3]	'		'		'
Other comprehensive income, Income tax (expense) benefit	0.1	[3]	-0.5	[3]	-1.7	[3]	-1	[3]
Reclassification adjustments, net of tax:	'		'		'		'
Amortization of net actuarial (gain) loss, net of tax	-0.4	[1]	0.3	[1]	-0.6	[1]	0.5	[1]
Amortization of prior service cost, net of tax	1.6	[1]	0.6	[1]	3.4	[1]	1.3	[1]
Other comprehensive income relating to VEBAs, net of tax	1.2		0.9		2.8		1.8
Available for sale securities:	'		'		'		'
Unrealized gain on available for sale securities, net of tax	0.1		0.1		0.2		0.3
Reclassification adjustments, net of tax:	'		'		'		'
Reclassification of unrealized gain upon sale of available for sale securities, net of tax	0	[2]	-0.1	[2]	-0.1	[2]	-0.4	[2]
Other comprehensive income (loss) relating to available for sale securities, net of tax	0.1		0		0.1		-0.1
Foreign currency translation adjustment, net of tax	-0.1		0.4		0.1		0.8
Cumulative tax rate adjustment, net of tax	0.9		'		'		'
Other comprehensive income, net of tax	$2.10		$1.30		$3		$2.50
[1]	Amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments were included as a component of Net periodic pension benefit income relating to VEBAs.
[2]	Amounts reclassified out of Accumulated other comprehensive income relating to sales of available for sale securities were included as a component of Other income (expense), net. The Company uses the specific identification method to determine the amount reclassified out of accumulated other comprehensive income.
[3]	Income tax amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments and sales of available for sale securities were included as a component of Income tax provision.

Guarantor_and_NonGuarantor_Fin2

Guarantor and Non-Guarantor Financial Statements, Textuals (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	23-May-12
In Millions, unless otherwise specified			Senior Notes
Condensed Financial Statements, Captions [Line Items]	'	'	'
Principal amount of notes	$225	$225	$225
Ownership interest by parent	100.00%	'	'

Guarantor_and_NonGuarantor_Fin3

Guarantor and Non-Guarantor Financial Statements, Balance Sheets (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Current assets:	'	'	'	'
Cash and cash equivalents	$174.20	$169.50	$281.70	$273.40
Short-term investments	127.2	129.5	'	'
Receivables:	'	'	'	'
Trade, less allowance for doubtful receivables	123.1	119.8	'	'
Intercompany receivables	0	0	'	'
Other	11	13.4	'	'
Inventories	198.1	214.4	'	'
Prepaid expenses and other current assets	135.5	44.2	'	'
Total current assets	769.1	690.8	'	'
Investments in and advances to subsidiaries	0	0	'	'
Property, plant, and equipment – net	441.4	429.3	'	'
Long-term intercompany receivables	0	0	'	'
Net assets of VEBAs	422.2	406	'	'
Deferred tax assets — net	45.8	69.1	'	'
Intangible assets – net	32.9	33.7	'	'
Goodwill	37.2	37.2	'	'
Other assets	24	104.8	'	'
Total	1,772.60	1,770.90	'	'
Current liabilities:	'	'	'	'
Accounts payable	72.1	62.9	'	'
Intercompany payable	0	0	'	'
Accrued salaries, wages, and related expenses	33.8	42.7	'	'
Other accrued liabilities	115.1	44.8	'	'
Current portion of long-term debt	167.9	0	'	'
Short-term capital lease	0.1	0.2	'	'
Total current liabilities	389	150.6	'	'
Deferred tax liability	1.2	1.2	'	'
Long-term intercompany payable	0	0	'	'
Long-term liabilities	63.7	146.4	'	'
Long-term debt	225	388.5	'	'
Total liabilities	678.9	686.7	'	'
Total stockholders’ equity	1,093.70	1,084.20	'	'
Total	1,772.60	1,770.90	'	'
Parent	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	5	5	5	5
Short-term investments	0	0	'	'
Receivables:	'	'	'	'
Trade, less allowance for doubtful receivables	0	0	'	'
Intercompany receivables	0	0	'	'
Other	0	0	'	'
Inventories	0	0	'	'
Prepaid expenses and other current assets	87.5	0.1	'	'
Total current assets	92.5	5.1	'	'
Investments in and advances to subsidiaries	1,505.40	1,437.90	'	'
Property, plant, and equipment – net	0	0	'	'
Long-term intercompany receivables	0	31.3	'	'
Net assets of VEBAs	0	0	'	'
Deferred tax assets — net	0	0	'	'
Intangible assets – net	0	0	'	'
Goodwill	0	0	'	'
Other assets	4.9	86.2	'	'
Total	1,602.80	1,560.50	'	'
Current liabilities:	'	'	'	'
Accounts payable	0.6	1.1	'	'
Intercompany payable	23.4	0	'	'
Accrued salaries, wages, and related expenses	0	0	'	'
Other accrued liabilities	92.2	3.5	'	'
Current portion of long-term debt	167.9	'	'	'
Short-term capital lease	0	0	'	'
Total current liabilities	284.1	4.6	'	'
Deferred tax liability	0	0	'	'
Long-term intercompany payable	0	0	'	'
Long-term liabilities	0	83.2	'	'
Long-term debt	225	388.5	'	'
Total liabilities	509.1	476.3	'	'
Total stockholders’ equity	1,093.70	1,084.20	'	'
Total	1,602.80	1,560.50	'	'
Guarantor Subsidiaries	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	164.7	157.7	275.7	266
Short-term investments	127.2	129.5	'	'
Receivables:	'	'	'	'
Trade, less allowance for doubtful receivables	119	117.7	'	'
Intercompany receivables	26.1	0.1	'	'
Other	5.1	5.3	'	'
Inventories	193.8	208.6	'	'
Prepaid expenses and other current assets	47.6	43.7	'	'
Total current assets	683.5	662.6	'	'
Investments in and advances to subsidiaries	28.1	26.5	'	'
Property, plant, and equipment – net	425.9	414	'	'
Long-term intercompany receivables	0	1.6	'	'
Net assets of VEBAs	422.2	406	'	'
Deferred tax assets — net	36.9	60.2	'	'
Intangible assets – net	32.9	33.7	'	'
Goodwill	37.2	37.2	'	'
Other assets	19	18.5	'	'
Total	1,685.70	1,660.30	'	'
Current liabilities:	'	'	'	'
Accounts payable	64.2	56.3	'	'
Intercompany payable	8.5	13.9	'	'
Accrued salaries, wages, and related expenses	30.3	39.3	'	'
Other accrued liabilities	21.7	39.9	'	'
Current portion of long-term debt	0	'	'	'
Short-term capital lease	0.1	0.2	'	'
Total current liabilities	124.8	149.6	'	'
Deferred tax liability	0	0	'	'
Long-term intercompany payable	16.2	40.7	'	'
Long-term liabilities	52.7	52	'	'
Long-term debt	0	0	'	'
Total liabilities	193.7	242.3	'	'
Total stockholders’ equity	1,492	1,418	'	'
Total	1,685.70	1,660.30	'	'
Non-Guarantor Subsidiaries	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	4.5	6.8	1	2.4
Short-term investments	0	0	'	'
Receivables:	'	'	'	'
Trade, less allowance for doubtful receivables	4.1	2.1	'	'
Intercompany receivables	0.7	0.2	'	'
Other	5.9	8.1	'	'
Inventories	5.1	6.4	'	'
Prepaid expenses and other current assets	0.4	0.4	'	'
Total current assets	20.7	24	'	'
Investments in and advances to subsidiaries	0	0	'	'
Property, plant, and equipment – net	15.5	15.3	'	'
Long-term intercompany receivables	16.2	9.5	'	'
Net assets of VEBAs	0	0	'	'
Deferred tax assets — net	0	0	'	'
Intangible assets – net	0	0	'	'
Goodwill	0	0	'	'
Other assets	0.1	0.1	'	'
Total	52.5	48.9	'	'
Current liabilities:	'	'	'	'
Accounts payable	7.3	5.5	'	'
Intercompany payable	2	0.1	'	'
Accrued salaries, wages, and related expenses	3.5	3.4	'	'
Other accrued liabilities	1.2	1.4	'	'
Current portion of long-term debt	0	'	'	'
Short-term capital lease	0	0	'	'
Total current liabilities	14	10.4	'	'
Deferred tax liability	1.2	1.2	'	'
Long-term intercompany payable	0	1.7	'	'
Long-term liabilities	11	11.2	'	'
Long-term debt	0	0	'	'
Total liabilities	26.2	24.5	'	'
Total stockholders’ equity	26.3	24.4	'	'
Total	52.5	48.9	'	'
Consolidating Adjustments	'	'	'	'
Current assets:	'	'	'	'
Cash and cash equivalents	0	0	0	0
Short-term investments	0	0	'	'
Receivables:	'	'	'	'
Trade, less allowance for doubtful receivables	0	0	'	'
Intercompany receivables	-26.8	-0.3	'	'
Other	0	0	'	'
Inventories	-0.8	-0.6	'	'
Prepaid expenses and other current assets	0	0	'	'
Total current assets	-27.6	-0.9	'	'
Investments in and advances to subsidiaries	-1,533.50	-1,464.40	'	'
Property, plant, and equipment – net	0	0	'	'
Long-term intercompany receivables	-16.2	-42.4	'	'
Net assets of VEBAs	0	0	'	'
Deferred tax assets — net	8.9	8.9	'	'
Intangible assets – net	0	0	'	'
Goodwill	0	0	'	'
Other assets	0	0	'	'
Total	-1,568.40	-1,498.80	'	'
Current liabilities:	'	'	'	'
Accounts payable	0	0	'	'
Intercompany payable	-33.9	-14	'	'
Accrued salaries, wages, and related expenses	0	0	'	'
Other accrued liabilities	0	0	'	'
Current portion of long-term debt	0	'	'	'
Short-term capital lease	0	0	'	'
Total current liabilities	-33.9	-14	'	'
Deferred tax liability	0	0	'	'
Long-term intercompany payable	-16.2	-42.4	'	'
Long-term liabilities	0	0	'	'
Long-term debt	0	0	'	'
Total liabilities	-50.1	-56.4	'	'
Total stockholders’ equity	-1,518.30	-1,442.40	'	'
Total	($1,568.40)	($1,498.80)	'	'

Guarantor_and_NonGuarantor_Fin4

Guarantor and Non-Guarantor Financial Statements, Comprehensive Income Statements (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME	'	'	'	'
Net sales	$344.10	$328.90	$679.20	$666.30
Cost of products sold:	'	'	'	'
Cost of products sold, excluding depreciation and amortization and other items	275.5	261.5	558.4	525.1
Unrealized (gains) losses on derivative instruments	-1.6	4.2	-3.6	4.9
Depreciation and amortization	7.7	7	15.1	14
Selling, administrative, research and development, and general	22	21.8	42.3	43.5
Net periodic pension benefit income relating to VEBAs	-6.1	-5.7	-11.7	-11.3
Total selling, administrative, research and development, and general	15.9	16.1	30.6	32.2
Other operating charges, net	0.2	0	0.2	0
Total costs and expenses	297.7	288.8	600.7	576.2
Operating (loss) income	46.4	40.1	78.5	90.1
Other (expense) income:	'	'	'	'
Interest (expense) income	-9.2	-9	-18	-18.3
Other income, net	1.8	-0.8	3.7	0.2
(Loss) income before income taxes	39	30.3	64.2	72
Income tax (provision) benefit	-14.5	-11.7	-23.9	-19.9
Earnings in equity of subsidiaries	0	0	0	0
Net income	24.5	18.6	40.3	52.1
Comprehensive income	26.6	19.9	43.3	54.6
Parent	'	'	'	'
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME	'	'	'	'
Net sales	0	0	0	0
Cost of products sold:	'	'	'	'
Cost of products sold, excluding depreciation and amortization and other items	0	0	0	0
Unrealized (gains) losses on derivative instruments	0	0	0	0
Depreciation and amortization	0	0	0	0
Selling, administrative, research and development, and general	1.2	1.1	2.2	1.5
Net periodic pension benefit income relating to VEBAs	0	0	0	0
Total selling, administrative, research and development, and general	1.2	1.1	2.2	1.5
Other operating charges, net	0	'	0	'
Total costs and expenses	1.2	1.1	2.2	1.5
Operating (loss) income	-1.2	-1.1	-2.2	-1.5
Other (expense) income:	'	'	'	'
Interest (expense) income	-9.3	-9	-18.6	-18.1
Other income, net	0.4	-0.9	1.4	-0.5
(Loss) income before income taxes	-10.1	-11	-19.4	-20.1
Income tax (provision) benefit	0	0	0	0
Earnings in equity of subsidiaries	34.6	29.6	59.7	72.2
Net income	24.5	18.6	40.3	52.1
Comprehensive income	26.6	19.9	43.3	54.6
Guarantor Subsidiaries	'	'	'	'
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME	'	'	'	'
Net sales	335.7	324.7	662.8	656.5
Cost of products sold:	'	'	'	'
Cost of products sold, excluding depreciation and amortization and other items	270.8	258.9	549.7	518.6
Unrealized (gains) losses on derivative instruments	-1.6	4.2	-3.6	4.9
Depreciation and amortization	7.5	6.8	14.6	13.5
Selling, administrative, research and development, and general	18.5	20.2	35.1	40.6
Net periodic pension benefit income relating to VEBAs	-6.1	-5.7	-11.7	-11.3
Total selling, administrative, research and development, and general	12.4	14.5	23.4	29.3
Other operating charges, net	0.2	'	0.2	'
Total costs and expenses	289.3	284.4	584.3	566.3
Operating (loss) income	46.4	40.3	78.5	90.2
Other (expense) income:	'	'	'	'
Interest (expense) income	0	0	0.4	-0.3
Other income, net	0.8	0.3	2	0.9
(Loss) income before income taxes	47.2	40.6	80.9	90.8
Income tax (provision) benefit	-17.8	-15.1	-30.4	-34.1
Earnings in equity of subsidiaries	1.4	-0.1	1.8	7.7
Net income	30.8	25.4	52.3	64.4
Comprehensive income	33	26.3	55.2	66.1
Non-Guarantor Subsidiaries	'	'	'	'
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME	'	'	'	'
Net sales	34	29.6	67.1	60
Cost of products sold:	'	'	'	'
Cost of products sold, excluding depreciation and amortization and other items	29.7	26.3	58.1	53.3
Unrealized (gains) losses on derivative instruments	0	0	0	0
Depreciation and amortization	0.2	0.2	0.5	0.5
Selling, administrative, research and development, and general	2.9	2.1	6.2	4.5
Net periodic pension benefit income relating to VEBAs	0	0	0	0
Total selling, administrative, research and development, and general	2.9	2.1	6.2	4.5
Other operating charges, net	0	'	0	'
Total costs and expenses	32.8	28.6	64.8	58.3
Operating (loss) income	1.2	1	2.3	1.7
Other (expense) income:	'	'	'	'
Interest (expense) income	0	0	0	0
Other income, net	0.7	-0.2	0.5	-0.1
(Loss) income before income taxes	1.9	0.8	2.8	1.6
Income tax (provision) benefit	-0.5	-0.7	-0.8	6.5
Earnings in equity of subsidiaries	0	0	0	0
Net income	1.4	0.1	2	8.1
Comprehensive income	1.3	0.5	2.1	8.9
Consolidating Adjustments	'	'	'	'
CONDENSED CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME	'	'	'	'
Net sales	-25.6	-25.4	-50.7	-50.2
Cost of products sold:	'	'	'	'
Cost of products sold, excluding depreciation and amortization and other items	-25	-23.7	-49.4	-46.8
Unrealized (gains) losses on derivative instruments	0	0	0	0
Depreciation and amortization	0	0	0	0
Selling, administrative, research and development, and general	-0.6	-1.6	-1.2	-3.1
Net periodic pension benefit income relating to VEBAs	0	0	0	0
Total selling, administrative, research and development, and general	-0.6	-1.6	-1.2	-3.1
Other operating charges, net	0	'	0	'
Total costs and expenses	-25.6	-25.3	-50.6	-49.9
Operating (loss) income	0	-0.1	-0.1	-0.3
Other (expense) income:	'	'	'	'
Interest (expense) income	0.1	0	0.2	0.1
Other income, net	-0.1	0	-0.2	-0.1
(Loss) income before income taxes	0	-0.1	-0.1	-0.3
Income tax (provision) benefit	3.8	4.1	7.3	7.7
Earnings in equity of subsidiaries	-36	-29.5	-61.5	-79.9
Net income	-32.2	-25.5	-54.3	-72.5
Comprehensive income	($34.30)	($26.80)	($57.30)	($75)

Guarantor_and_NonGuarantor_Fin5

Guarantor and Non-Guarantor Financial Statements, Cash Flow Statements (Details) (USD $)	6 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:	'	'
Net cash (used in) provided by operating activities	$71.30	$48.90
Cash flows from investing activities:	'	'
Capital expenditures	-30.1	-26
Purchase of available for sale securities	-23.4	-98.2
Proceeds from disposition of available for sale securities	25	135.7
Change in restricted cash	0	0.7
Net cash provided by (used in) investing activities	-28.5	12.2
Cash flows from financing activities:	'	'
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0.8	0.9
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	-2.4	-2.2
Repurchase of common stock	-23.7	-39.9
Cash dividend paid to stockholders	-12.8	-11.6
Intercompany loan	0	0
Net cash provided by (used in) financing activities	-38.1	-52.8
Net increase (decrease) in cash and cash equivalents during the period	4.7	8.3
Cash and cash equivalents at beginning of period	169.5	273.4
Cash and cash equivalents at end of period	174.2	281.7
Parent	'	'
Cash flows from operating activities:	'	'
Net cash (used in) provided by operating activities	7.6	-14.4
Cash flows from investing activities:	'	'
Capital expenditures	0	0
Purchase of available for sale securities	0	0
Proceeds from disposition of available for sale securities	0	0
Change in restricted cash	'	0
Net cash provided by (used in) investing activities	0	0
Cash flows from financing activities:	'	'
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0	0
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	-2.4	-2.2
Repurchase of common stock	-23.7	-39.9
Cash dividend paid to stockholders	-12.8	-11.6
Intercompany loan	31.3	68.1
Net cash provided by (used in) financing activities	-7.6	14.4
Net increase (decrease) in cash and cash equivalents during the period	0	0
Cash and cash equivalents at beginning of period	5	5
Cash and cash equivalents at end of period	5	5
Guarantor Subsidiaries	'	'
Cash flows from operating activities:	'	'
Net cash (used in) provided by operating activities	56.9	60.4
Cash flows from investing activities:	'	'
Capital expenditures	-29.4	-25
Purchase of available for sale securities	-23.4	-98.2
Proceeds from disposition of available for sale securities	25	135.7
Change in restricted cash	'	0.7
Net cash provided by (used in) investing activities	-27.8	13.2
Cash flows from financing activities:	'	'
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0.8	0.9
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	0	0
Repurchase of common stock	0	0
Cash dividend paid to stockholders	0	0
Intercompany loan	-22.9	-64.8
Net cash provided by (used in) financing activities	-22.1	-63.9
Net increase (decrease) in cash and cash equivalents during the period	7	9.7
Cash and cash equivalents at beginning of period	157.7	266
Cash and cash equivalents at end of period	164.7	275.7
Non-Guarantor Subsidiaries	'	'
Cash flows from operating activities:	'	'
Net cash (used in) provided by operating activities	6.8	2.9
Cash flows from investing activities:	'	'
Capital expenditures	-0.7	-1
Purchase of available for sale securities	0	0
Proceeds from disposition of available for sale securities	0	0
Change in restricted cash	'	0
Net cash provided by (used in) investing activities	-0.7	-1
Cash flows from financing activities:	'	'
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0	0
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	0	0
Repurchase of common stock	0	0
Cash dividend paid to stockholders	0	0
Intercompany loan	-8.4	-3.3
Net cash provided by (used in) financing activities	-8.4	-3.3
Net increase (decrease) in cash and cash equivalents during the period	-2.3	-1.4
Cash and cash equivalents at beginning of period	6.8	2.4
Cash and cash equivalents at end of period	4.5	1
Consolidating Adjustments	'	'
Cash flows from operating activities:	'	'
Net cash (used in) provided by operating activities	0	0
Cash flows from investing activities:	'	'
Capital expenditures	0	0
Purchase of available for sale securities	0	0
Proceeds from disposition of available for sale securities	0	0
Change in restricted cash	'	0
Net cash provided by (used in) investing activities	0	0
Cash flows from financing activities:	'	'
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0	0
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	0	0
Repurchase of common stock	0	0
Cash dividend paid to stockholders	0	0
Intercompany loan	0	0
Net cash provided by (used in) financing activities	0	0
Net increase (decrease) in cash and cash equivalents during the period	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	$0	$0

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	6 Months Ended		12 Months Ended	0 Months Ended	6 Months Ended	0 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jul. 15, 2014	Jun. 30, 2014	Jul. 15, 2014	Jun. 30, 2014	Jul. 15, 2014	Jun. 30, 2014	Jun. 30, 2013	Jul. 15, 2014
				Subsequent Event	Convertible Notes	Convertible Notes	Call Options	Call Options	Warrants	Warrants	Warrants
						Subsequent Event		Subsequent Event			Subsequent Event
Subsequent Event [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Cash dividend declared per common share	'	'	'	$0.35	'	'	'	'	'	'	'
Cash dividends declared	'	'	'	$6,300,000	'	'	'	'	'	'	'
Conversion rate of common stock shares per $1,000 of principal amount	'	'	'	'	20.8549	20.8862	'	'	'	'	'
Principal amount in conversion feature	'	'	'	'	1,000	1,000	'	'	'	'	'
Conversion price per share of note	'	'	'	'	$47.95	$47.88	'	'	'	'	'
Exercise price per share of Call Options	'	'	'	'	'	'	$47.95	$47.88	'	'	'
Exercise price per share of Warrants	'	'	'	'	'	'	'	'	60.89	61.19	60.8
Repurchase of common stock, shares	346,781	654,277	'	'	'	'	'	'	'	'	'
Weighted-average price per share of common stock repurchased	$69.25	$61.95	'	'	'	'	'	'	'	'	'
Common share amount available for additional share repurchase	$93,600,000	'	$117,600,000	'	'	'	'	'	'	'	'