Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 570	$ 633	$ 684	$ 768
Balance at end of period	402	955	402	955
Pension and other postretirement benefit plans, tax (less than)	0	1	28	(2)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(651)	(705)	(742)	(649)
Other comprehensive income before reclassifications			(29)
Reclassifications from accumulated other comprehensive loss to net earnings			87
Net other comprehensive income			58
Balance at end of period	(684)	$ (703)	(684)	$ (703)
Foreign Currency Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period			(339)
Other comprehensive income before reclassifications			(27)
Reclassifications from accumulated other comprehensive loss to net earnings			0
Net other comprehensive income			(27)
Balance at end of period	(366)		(366)
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			(3)
Reclassifications from accumulated other comprehensive loss to net earnings			91
Net other comprehensive income			88
Balance at end of period	(319)		(319)
Pension and other postretirement benefit plans, tax (less than)			29
Unrealized Gain (Loss) on Foreign Forward Exchange Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period			4
Other comprehensive income before reclassifications			1
Reclassifications from accumulated other comprehensive loss to net earnings			(4)
Net other comprehensive income			(3)
Balance at end of period	$ 1		$ 1