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Derivative Instruments And Hedging Activities (Narrative) (Details)
In Millions, unless otherwise specified |
6 Months Ended | 12 Months Ended | 12 Months Ended | 12 Months Ended | 12 Months Ended | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Dec. 31, 2011
USD ($)
|
Dec. 31, 2011
USD ($)
|
Dec. 31, 2010
USD ($)
|
Dec. 31, 2009
USD ($)
|
Dec. 31, 2010
Gain Loss On Settlement Of Derivative Instrument [Member]
USD ($)
|
Dec. 31, 2009
Gain Loss On Settlement Of Derivative Instrument [Member]
USD ($)
|
Dec. 31, 2011
Foreign Exchange Contracts [Member]
USD ($)
|
Dec. 31, 2010
Foreign Exchange Contracts [Member]
USD ($)
|
Dec. 31, 2009
Foreign Exchange Contracts [Member]
USD ($)
|
Dec. 31, 2011
Foreign Exchange Contracts [Member]
AUD
|
Dec. 31, 2010
Foreign Exchange Contracts [Member]
AUD
|
Dec. 31, 2009
Foreign Exchange Contracts [Member]
AUD
|
Dec. 31, 2011
Foreign Exchange Contract Hedge Designation [Member]
USD ($)
|
Dec. 31, 2010
Australian Hedge Contracts [Member]
USD ($)
|
Dec. 31, 2011
Australian Hedge Contracts [Member]
|
Dec. 31, 2011
Customer Contracts [Member]
USD ($)
|
Dec. 31, 2010
Customer Contracts [Member]
USD ($)
|
Dec. 31, 2011
Customer Contracts [Member]
Product Revenues [Member]
USD ($)
|
Dec. 31, 2010
Customer Contracts [Member]
Product Revenues [Member]
USD ($)
|
Dec. 31, 2009
Customer Contracts [Member]
Product Revenues [Member]
USD ($)
|
Dec. 31, 2011
U.S. Iron Ore And Eastern Canadian Iron Ore [Member]
USD ($)
|
Dec. 31, 2011
Eastern Canadian Iron Ore [Member]
Provisional Pricing Arrangements [Member]
Product Revenues [Member]
USD ($)
|
Dec. 31, 2011
U.S. Iron Ore [Member]
Provisional Pricing Arrangements [Member]
USD ($)
|
Dec. 31, 2011
Consolidated Thompson [Member]
Foreign Exchange Contracts [Member]
USD ($)
|
Jan. 11, 2011
Consolidated Thompson [Member]
Foreign Exchange Contracts [Member]
CAD
|
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| Description of Cash Flow Hedge Activity | The policy allows for not more than 75 percent, but not less than 40 percent for up to 12 months and not less than 10 percent for up to 15 months, of forecasted net currency exposures that are probable to occur. For our Asia Pacific operations, the forecasted net currency exposures are in relation to anticipated operating costs designated as cash flow hedges on future sales. Prior to the implementation of this policy, our Asia Pacific operations had a policy in place that was specific to local operations and allowed no more than 75 percent of anticipated operating costs for up to 12 months and no more than 50 percent of operating costs for up to 24 months to be designated as cash flow hedges of future sales. | ||||||||||||||||||||||||
| Amount of gain/(loss) recognized in income on derivative | $ 6.5 | $ 960.7 | $ (28.2) | $ 39.8 | $ 85.7 | $ 178.0 | $ 120.2 | $ 22.2 | $ 809.1 | $ 309.4 | |||||||||||||||
| Notional amounts of outstanding exchange rate contracts | 400.0 | 70.0 | |||||||||||||||||||||||
| Foreign currency spot rate | 1.02 | 1.02 | 0.90 | 1.02 | 1.02 | ||||||||||||||||||||
| Gain Loss On Foreign Currency Derivative Instruments Not Designated As Hedging Instruments | 101.9 | 39.8 | 85.7 | 8.8 | 93.1 | ||||||||||||||||||||
| Notional Amount of Foreign Currency Derivative Instruments Not Designated as Hedging Instruments | 15.0 | 230.0 | 4,700.0 | ||||||||||||||||||||||
| Amount that will be reclassified to Product revenues in the next 12 months upon settlement of the related contracts | 1.2 | ||||||||||||||||||||||||
| Unrealized Gain (Loss) on Cash Flow Hedging Instruments | 1.8 | 1.9 | |||||||||||||||||||||||
| Derivative assets | 82.1 | 82.1 | 82.6 | 72.9 | 45.6 | 1.2 | |||||||||||||||||||
| Other current liabilities | 148.1 | 148.1 | 80.6 | 19.5 | |||||||||||||||||||||
| Accounts receivable | $ 304.2 | $ 304.2 | $ 359.1 | $ 83.8 | |||||||||||||||||||||
| Interest acquired | 79.00% | 79.00% | |||||||||||||||||||||||