Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 684	$ 768
Balance at end of period	388	65
Pension and other postretirement benefit plans, tax (less than)	28	1
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(742)	(649)
Other comprehensive income before reclassifications	110
Reclassifications from accumulated other comprehensive loss to net earnings	(1)
Net other comprehensive income	109
Balance at end of period	(633)	$ (630)
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(339)
Other comprehensive income before reclassifications	19
Reclassifications from accumulated other comprehensive loss to net earnings	0
Net other comprehensive income	19
Balance at end of period	(320)
Pension and Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(407)
Other comprehensive income before reclassifications	85
Reclassifications from accumulated other comprehensive loss to net earnings	1
Net other comprehensive income	86
Balance at end of period	(321)
Pension and other postretirement benefit plans, tax (less than)	1
Unrealized Gain (Loss) on Forward Exchange Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	4
Other comprehensive income before reclassifications	6
Reclassifications from accumulated other comprehensive loss to net earnings	(2)
Net other comprehensive income	4
Balance at end of period	$ 8