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Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Narrative) (Details)

v3.3.0.814
DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (Narrative) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2015
Mar. 31, 2015
Sep. 30, 2014
Sep. 30, 2015
Sep. 30, 2014
Dec. 31, 2014
Jun. 30, 2014
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net $ 16.0 Ìý $ 64.9 $ 3.1 $ 103.4 Ìý Ìý
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net (4.4) Ìý 0.6 (18.5) (18.8) Ìý Ìý
Canadian Dollar Foreign Exchange Contracts Hedge Prior to De Designation [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Ìý Ìý Ìý 0.0 (0.5) Ìý Ìý
Interest Rate Swap [Member] | Other Nonoperating Income (Expense) [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Gain (Loss) on Fair Value Hedge Ineffectiveness, Net Ìý Ìý 0.1 Ìý 0.3 Ìý Ìý
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative, Notional Amount Ìý Ìý Ìý Ìý Ìý Ìý $ 250.0
Australian Dollar Foreign Exchange Contract Hedge Designation [Member] | Product Revenues [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net (0.1) $ (6.3) 1.6 (7.4) (11.2) Ìý Ìý
Australian Dollar Foreign Exchange Contract Hedge Designation [Member] | Designated as Hedging Instrument [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative, Notional Amount 0.0 Ìý Ìý 0.0 Ìý $ 220.0 Ìý
Australian Dollar Foreign Exchange Contract Hedge Designation [Member] | Designated as Hedging Instrument [Member] | Accumulated Other Comprehensive Income (Loss) [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Amount that will be reclassified to product revenues in the next 12 months upon settlement of the related contracts 0.0 Ìý Ìý 0.0 Ìý Ìý Ìý
Australian Dollar Foreign Exchange Contract Prior To De Designation [Member] | Not Designated as Hedging Instrument [Member] | Accumulated Other Comprehensive Income (Loss) [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Amount that will be reclassified to product revenues in the next 12 months upon settlement of the related contracts (0.4) Ìý Ìý (0.4) Ìý Ìý Ìý
Canadian Dollar Foreign Exchange Contracts Hedge Designation [Member] | Cost of Sales [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net 0.0 Ìý (1.0) 0.0 (7.1) Ìý Ìý
Canadian Dollar Foreign Exchange Contracts Hedge De Designated [Member] [Member] | Not Designated as Hedging Instrument [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative, Notional Amount 0.0 Ìý Ìý 0.0 Ìý 0.0 Ìý
Foreign Exchange Contract [Member] | Other Nonoperating Income (Expense) [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [1] (1.1) Ìý 0.0 (3.6) (3.3) Ìý Ìý
Foreign Exchange Contract [Member] | Product Revenues [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net (2.1) Ìý 0.0 (11.8) 0.0 Ìý Ìý
Customer Supply Agreement [Member] | Not Designated as Hedging Instrument [Member] | Product Revenues [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Amount of gain/(loss) recognized in income on derivative 11.6 Ìý 62.6 22.1 124.6 Ìý Ìý
Customer Supply Agreement [Member] | Not Designated as Hedging Instrument [Member] | Derivative Financial Instruments, Assets [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative assets 9.8 Ìý Ìý 9.8 Ìý 63.2 Ìý
Provisional Pricing Arrangements [Member] | Product Revenues [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net 7.6 Ìý 2.3 (0.2) (17.9) Ìý Ìý
Provisional Pricing Arrangements [Member] | Not Designated as Hedging Instrument [Member] | U S Iron Ore And Asia Pacific Iron Ore [Member] | Product Revenues [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Amount of gain/(loss) recognized in income on derivative 7.6 Ìý 2.3 (0.2) (17.9) Ìý Ìý
Provisional Pricing Arrangements [Member] | Not Designated as Hedging Instrument [Member] | U S Iron Ore And Asia Pacific Iron Ore [Member] | Derivative Financial Instruments, Assets [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative assets 0.6 Ìý Ìý 0.6 Ìý 0.0 Ìý
Provisional Pricing Arrangements [Member] | Not Designated as Hedging Instrument [Member] | U S Iron Ore And Asia Pacific Iron Ore [Member] | Derivative Financial Instruments, Liabilities [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative liabilities 0.8 Ìý Ìý 0.8 Ìý 9.5 Ìý
Corporate [Member] | Canadian Dollar Foreign Exchange Contracts Hedge Prior to De Designation [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Ìý Ìý 0.0 Ìý (0.5) Ìý Ìý
Corporate [Member] | Canadian Dollar Foreign Exchange Contracts Hedge De Designated [Member] [Member] | Not Designated as Hedging Instrument [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative, Notional Amount $ 0.0 Ìý Ìý $ 0.0 Ìý 183.0 Ìý
Corporate [Member] | Foreign Exchange Contract [Member] | Cost of Sales [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Ìý Ìý $ 0.0 Ìý $ (3.3) $ (7.3) Ìý
[1] At September 30, 2014, the location of the Gain (Loss) Recognized in Income on Derivative for Foreign Exchange Contracts was Cost of goods sold and operating expenses.