Derivatives - Effect on Income (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Gain (loss) on derivative
Carrying Amount of Hedged Asset/(Liabilities)	$ 56,400,000	$ 50,900,000	$ 56,400,000	$ 50,900,000
Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Asset/(Liabilities)	1,900,000	2,700,000	1,900,000	2,700,000
Revenue	10,150,800,000	8,086,200,000	19,332,200,000	16,280,400,000
Cost of revenue	9,904,700,000	7,855,200,000	18,842,600,000	15,818,000,000.0
Gains or Loss on fair value hedge relationships
Gain (Loss) recognized in earnings related to fair value or cash flow hedges excluded from assessment of hedge effectiveness	0	0	0	0
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	(3,700,000)	5,400,000	1,300,000	12,500,000
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	(10,200,000)	5,400,000	4,500,000	2,000,000.0
Potential Collateral Requirements for Derivative Liabilities with Credit-Risk-Contingent Features
Net derivatives liability positions with credit contingent features	13,000,000.0		13,000,000.0		$ 11,800,000
Maximum potential collateral requirements	13,000,000.0		13,000,000.0		11,800,000
Collateral posted and held by our counterparties	0		0		$ 0
Revenue
Gain (loss) on derivative
Revenue	10,150,800,000	8,086,200,000	19,332,200,000	16,280,400,000
Gains or Loss on fair value hedge relationships
Hedged Item	0	0	0	0
Derivatives designated as hedging instruments	0	0	0	0
Total amount of income and expense line items excluding the impact of hedges, Revenue	10,171,200,000	8,070,200,000	19,356,100,000	16,274,700,000
Cost of revenue
Gain (loss) on derivative
Cost of revenue	9,904,700,000	7,855,200,000	18,842,600,000	15,818,000,000.0
Gains or Loss on fair value hedge relationships
Hedged Item	11,300,000	1,500,000	16,700,000	(2,000,000.0)
Derivatives designated as hedging instruments	(10,900,000)	1,400,000	(16,500,000)	6,700,000
Total amount of income and expense line items excluding the impact of hedges, Cost of Revenue	9,915,200,000	7,847,500,000	18,871,200,000	15,818,900,000
Commodity contracts | Revenue
Gains or Loss on fair value hedge relationships
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	(25,300,000)	49,300,000	(27,600,000)	106,400,000
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	(20,300,000)	15,900,000	(23,900,000)	5,800,000
Commodity contracts | Cost of revenue
Gains or Loss on fair value hedge relationships
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	19,500,000	(43,900,000)	29,700,000	(93,900,000)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	10,200,000	(10,600,000)	28,400,000	(3,800,000)
Foreign currency contracts | Other Income (expense) net
Gains or Loss on fair value hedge relationships
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	2,100,000	0	(800,000)	0
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	0	0	0	0
Derivatives not designated as hedging instruments
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	(2,700,000)	15,200,000	4,500,000	23,600,000
Derivatives not designated as hedging instruments | Commodity contracts
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	(10,400,000)	21,700,000	300,000	32,100,000
Derivatives not designated as hedging instruments | Commodity contracts | Revenue
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	(3,600,000)	19,100,000	44,000,000.0	68,200,000
Derivatives not designated as hedging instruments | Commodity contracts | Cost of revenue
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	(6,800,000)	2,600,000	(43,800,000)	(36,200,000)
Derivatives not designated as hedging instruments | Foreign currency contracts
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	7,700,000	(6,500,000)	4,200,000	(8,500,000)
Derivatives not designated as hedging instruments | Foreign currency contracts | Revenue
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	1,500,000	(1,600,000)	900,000	(2,100,000)
Derivatives not designated as hedging instruments | Foreign currency contracts | Other Income (expense) net
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	6,200,000	(4,800,000)	3,400,000	(6,400,000)
Accumulated gain (loss), cash flow hedge, including noncontrolling interest | Reclassification out of AOCI | Revenue
Gain (loss) on derivative
Revenue	(20,300,000)	15,900,000	(23,900,000)	5,800,000
Accumulated gain (loss), cash flow hedge, including noncontrolling interest | Reclassification out of AOCI | Cost of revenue
Gain (loss) on derivative
Cost of revenue	$ 10,200,000	$ (10,600,000)	$ 28,400,000	$ (3,800,000)