Derivative Instruments And Hedging Activities (Schedule Of Derivative Instruments In Statement Of Financial Position, Fair Value) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 79.4	$ 165.9
Derivative liability, fair value	13.0	23.0
Accounts Receivable [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value		83.8
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	22.4	5.2
Derivative liability, fair value	1.3	3.5
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Derivative Assets (Current) [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	22.4	5.2
Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	1.3	3.5
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	57.0	160.7
Derivative liability, fair value	11.7	19.5
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value
Derivative liability, fair value
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Derivative Assets (Current) [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value		2.8
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Assets Held-for-sale [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	1.1
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Liabilities Of Assets Held For Sale [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, fair value
Not Designated as Hedging Instrument [Member] | Customer Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, fair value
Not Designated as Hedging Instrument [Member] | Customer Contracts [Member] | Derivative Assets (Current) [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value		72.9
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value
Derivative liability, fair value
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Derivative Assets (Current) [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value		1.2
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Accounts Receivable [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value		83.8
Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	11.7	19.5
Market Approach [Member] | Provisional Pricing Arrangements [Member] | Managements Estimate Of 62% Fee [Member] | Not Designated as Hedging Instrument [Member] | Provisional Pricing Arrangements [Member] | Derivative Assets (Current) [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	1.4
Market Approach [Member] | Customer Contracts [Member] | Hot-Rolled Steel Estimate [Member] | Not Designated as Hedging Instrument [Member] | Customer Contracts [Member] | Derivative Assets (Current) [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 54.5