Supplementary Information Foreign Currency Exchange Gain (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		4 Months Ended	8 Months Ended	12 Months Ended
	Sep. 30, 2019	Mar. 31, 2018	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2019		Dec. 31, 2018
Foreign Currency Exchange Gain (Loss) [Line Items]
Foreign Currency Transaction (Loss) Gain, before Tax			$ (23)	$ (364)	$ (99)	[1],[2]	$ (127)	[1],[2],[3],[4]
Foreign Currency Transaction Gain (Loss) Tax Benefits (Expenses)			(29)	371	15		(52)
Foreign Currency Transaction (Loss) Gain After Tax			(52)	7	(84)		(179)
Subsidiary Monetary Position
Foreign Currency Exchange Gain (Loss) [Line Items]
Foreign Currency Transaction (Loss) Gain, before Tax			(114)	67	(41)	[1]	(221)	[1]
Foreign Currency Transaction Gain (Loss) Tax Benefits (Expenses)			4	216	2		(31)
Foreign Currency Transaction (Loss) Gain After Tax			(110)	283	(39)		(252)
Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Foreign Currency Transaction (Loss) Gain, before Tax			91	(431)	(58)		94	[4]
Foreign Currency Transaction Gain (Loss) Tax Benefits (Expenses)			(33)	155	13		(21)
Foreign Currency Transaction (Loss) Gain After Tax			$ 58	$ (276)	(45)		73
Tax Reform Foreign Currency Exchange Impact [Member] | Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Foreign Currency Transaction (Loss) Gain, before Tax		$ (50)					(50)
Argentina, Pesos | Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Foreign Currency Transaction (Loss) Gain, before Tax					(51)
Argentine peso devaluation [Member] | Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Foreign Currency Transaction (Loss) Gain, before Tax	$ (33)				$ (51)		$ (68)

[1] Includes a net $(51) million and $(68) million pre-tax exchange loss associated with the devaluation of the Argentine peso for the year ended December 31, 2019 and December 31, 2018, respectively.

[2] Includes a net $(51) million and $(68) million pre-tax exchange loss associated with the devaluation of the Argentine peso for the year ended December 31, 2019 and December 31, 2018, respectively.

[3] Includes a $(50) million foreign exchange loss for the year ended December 31, 2018 related to adjustments to foreign currency exchange contracts as a result of U.S. tax reform, which is included within significant items.

[4] Includes a $(50) million foreign exchange loss for the year ended December 31, 2018 related to adjustments to foreign currency exchange contracts as a result of U.S. tax reform.