Derivatives - Effect on Income (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Gain (loss) on derivative
Carrying Amount of Hedged Asset/(Liabilities)	$ 68,500,000	$ 50,900,000	$ 68,500,000	$ 50,900,000
Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of the Hedged Asset/(Liabilities)	4,700,000	2,700,000	4,700,000	2,700,000
Revenue	10,429,500,000	8,543,000,000.0	29,761,700,000	24,823,400,000
Cost of revenue	10,162,800,000	8,303,100,000	29,005,400,000	24,121,100,000
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	300,000	(14,300,000)	1,600,000	(1,800,000)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	5,500,000	(5,600,000)	9,900,000	(3,600,000)
Potential Collateral Requirements for Derivative Liabilities with Credit-Risk-Contingent Features
Net derivatives liability positions with credit contingent features	11,100,000		11,100,000		$ 11,800,000
Maximum potential collateral requirements	11,100,000		11,100,000		11,800,000
Collateral posted and held by our counterparties	0		0		$ 0
Revenue
Gain (loss) on derivative
Revenue	10,429,500,000	8,543,000,000.0	29,761,700,000	24,823,400,000
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	10,436,100,000	8,551,400,000	29,792,300,000	24,826,000,000.0
Cost of revenue
Gain (loss) on derivative
Cost of revenue	10,162,800,000	8,303,100,000	29,005,400,000	24,121,100,000
Gains or Loss on fair value hedge relationships
Hedged Item	8,700,000	800,000	25,400,000	(1,300,000)
Derivatives designated as hedging instruments	(7,100,000)	(23,100,000)	(23,500,000)	(16,400,000)
Total amount of income and expense line items excluding the impact of hedges, Cost of Revenue	10,177,200,000	8,283,600,000	29,048,400,000	24,102,500,000
Commodity contracts | Revenue
Gains or Loss on fair value hedge relationships
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	(46,400,000)	(83,000,000.0)	(74,100,000)	23,300,000
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	(6,600,000)	(8,400,000)	(30,600,000)	(2,600,000)
Commodity contracts | Cost of revenue
Gains or Loss on fair value hedge relationships
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income	46,900,000	68,700,000	77,000,000.0	(25,200,000)
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	12,700,000	2,800,000	41,100,000	(1,000,000.0)
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	(100,000)	0	(1,300,000)	0
Amount of Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Income	(700,000)	0	(700,000)	0
Derivatives not designated as hedging instruments
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	(5,800,000)	13,200,000	(1,300,000)	36,800,000
Derivatives not designated as hedging instruments | Commodity contracts
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	(3,900,000)	16,700,000	(3,600,000)	48,800,000
Derivatives not designated as hedging instruments | Commodity contracts | Revenue
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	17,500,000	(31,200,000)	61,600,000	37,100,000
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)	(21,400,000)	47,900,000	(65,200,000)	11,700,000
Derivatives not designated as hedging instruments | Foreign currency contracts
Gains or Loss on fair value hedge relationships
Amount of Realized and Unrealized Gain (Loss)	(1,900,000)	(3,500,000)	2,300,000	(12,000,000.0)
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)	200,000	(1,000,000.0)	1,100,000	(3,100,000)
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)	(2,100,000)	(2,500,000)	1,200,000	(8,900,000)
Accumulated gain (loss), cash flow hedge, including noncontrolling interest | Reclassification out of AOCI | Revenue
Gain (loss) on derivative
Revenue	(6,600,000)	(8,400,000)	(30,600,000)	(2,600,000)
Accumulated gain (loss), cash flow hedge, including noncontrolling interest | Reclassification out of AOCI | Cost of revenue
Gain (loss) on derivative
Cost of revenue	$ 12,700,000	$ 2,800,000	$ 41,100,000	$ (1,000,000.0)