Derivatives and Fair Value Measurements (Details 1) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2015		Sep. 30, 2014		Jun. 30, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$ 400.2				$ 400.2				$ 0.0	$ 0.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	335.8				335.8
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	68.4				68.4
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	0.1		$ 31.9		14.9		$ 106.7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(0.5)				(0.5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Gain (Loss) Included in Other Comprehensive Income (Loss)	181.3				181.3
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(116.4)				(116.4)
Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in income on non-designated derivatives	0.0		0.0		0.0		0.0
Operating costs and expenses [Member] | Cash flow hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain recognized in other comprehensive income on derivatives (effective portion)	(181.3)		(275.0)		(164.5)		10.6
(Loss) gain reclassified from other comprehensive income into income (effective portion)	(116.4)	[1]	8.6	[2]	(327.9)	[3]	(6.2)	[4]
Gain (loss) reclassified from other comprehensive income into income (ineffective portion)	(0.5)		(1.8)		1.3		(1.0)
Commodity swap contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	106.7				106.7				0.0	0.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	76.0				76.0
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	15.5				15.5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	(0.5)				(0.5)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Gain (Loss) Included in Other Comprehensive Income (Loss)	63.1				63.1
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(31.9)				(31.9)
Commodity swap contracts [Member] | Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in income on non-designated derivatives	0.0		0.0		0.0		0.0
Commodity swap contracts [Member] | Operating costs and expenses [Member] | Cash flow hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain recognized in other comprehensive income on derivatives (effective portion)	(63.1)		(47.3)		(27.3)		(38.1)
(Loss) gain reclassified from other comprehensive income into income (effective portion)	(31.9)	[1]	(1.0)	[2]	(89.0)	[3]	(3.3)	[4]
Gain (loss) reclassified from other comprehensive income into income (ineffective portion)	(0.5)		(1.8)		1.3		(1.0)
Foreign currency forward contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	293.5				293.5				$ 0.0	$ 0.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	259.8				259.8
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	52.9				52.9
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	0.0				0.0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Gain (Loss) Included in Other Comprehensive Income (Loss)	118.2				118.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(84.5)				(84.5)
Foreign currency forward contract [Member] | Operating costs and expenses [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain recognized in income on non-designated derivatives	0.0		0.0		0.0		0.0
Foreign currency forward contract [Member] | Operating costs and expenses [Member] | Cash flow hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
(Loss) gain recognized in other comprehensive income on derivatives (effective portion)	(118.2)		(227.7)		(137.2)		48.7
(Loss) gain reclassified from other comprehensive income into income (effective portion)	(84.5)	[1]	9.6	[2]	(238.9)	[3]	(2.9)	[4]
Gain (loss) reclassified from other comprehensive income into income (ineffective portion)	$ 0.0		$ 0.0		$ 0.0		$ 0.0
Risk Level, Low [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Credit and non-performance risk, level 3 unobservable input as a percentage of overall valuation	26.00%				26.00%
Risk Level, High [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Credit and non-performance risk, level 3 unobservable input as a percentage of overall valuation	39.00%				39.00%
Weighted Average [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Credit and non-performance risk, level 3 unobservable input as a percentage of overall valuation	31.00%				31.00%

[1] Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $0.1 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.

[2] Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $31.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.

[3] Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $14.9 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.

[4] Includes the reclassification from "Accumulated other comprehensive loss" into earnings of $106.7 million of previously unrecognized gains on foreign currency cash flow hedge contracts monetized in the fourth quarter of 2012.