Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net unrealized (losses) gains on cash flow hedges, net of taxes, beginning of period			$ 711
Other comprehensive income before reclassifications			(77)
Reclassifications from accumulated other comprehensive loss to net earnings			13
Net other comprehensive income			(64)
Net unrealized (losses) gains on cash flow hedges, net of taxes, end of period	$ 905		905
Pension and other postretirement benefit plans, tax	1	$ 1	(2)	$ 0
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net unrealized (losses) gains on cash flow hedges, net of taxes, beginning of period			(649)
Net unrealized (losses) gains on cash flow hedges, net of taxes, end of period	(703)		(703)
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net unrealized (losses) gains on cash flow hedges, net of taxes, beginning of period			(239)
Other comprehensive income before reclassifications			(54)
Reclassifications from accumulated other comprehensive loss to net earnings			0
Net other comprehensive income			(54)
Net unrealized (losses) gains on cash flow hedges, net of taxes, end of period	(293)		(293)
Pension and Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net unrealized (losses) gains on cash flow hedges, net of taxes, beginning of period			(402)
Other comprehensive income before reclassifications			(14)
Reclassifications from accumulated other comprehensive loss to net earnings			10
Net other comprehensive income			(4)
Net unrealized (losses) gains on cash flow hedges, net of taxes, end of period	(406)		(406)
Pension and other postretirement benefit plans, tax			2
Unrealized Gain (Loss) on Forward Exchange Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net unrealized (losses) gains on cash flow hedges, net of taxes, beginning of period	(1)	1	2	2
Other comprehensive income before reclassifications			(9)
Reclassifications from accumulated other comprehensive loss to net earnings			3
Net other comprehensive income			(6)
Net unrealized (losses) gains on cash flow hedges, net of taxes, end of period	(4)	$ 4	(4)	$ 4
Unrealized Gain (Loss) on Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Net unrealized (losses) gains on cash flow hedges, net of taxes, beginning of period			(10)
Other comprehensive income before reclassifications			0
Reclassifications from accumulated other comprehensive loss to net earnings			0
Net other comprehensive income			0
Net unrealized (losses) gains on cash flow hedges, net of taxes, end of period	0		0
Accounting Standards Update 2016-01
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified to retained income	10		10
Accounting Standards Update 2016-01 | Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified to retained income	0		0
Accounting Standards Update 2016-01 | Pension and Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified to retained income	0		0
Accounting Standards Update 2016-01 | Unrealized Gain (Loss) on Forward Exchange Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified to retained income	0		0
Accounting Standards Update 2016-01 | Unrealized Gain (Loss) on Investments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Amounts reclassified to retained income	$ 10		$ 10