Supplementary Information Foreign Currency Exchange Gain (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (loss) gain	[1],[2]	$ (174)	$ (99)	$ (127)
Tax benefits (expenses) on exchange (loss) gain		13	15	(52)
Net after-tax exchange (loss) gain		(161)	(84)	(179)
Subsidiary Monetary Position
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (loss) gain		(263)	(41)	(221)
Tax benefits (expenses) on exchange (loss) gain		34	2	(31)
Net after-tax exchange (loss) gain		(229)	(39)	(252)
Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (loss) gain		89	(58)	94
Tax benefits (expenses) on exchange (loss) gain		(21)	13	(21)
Net after-tax exchange (loss) gain		68	(45)	73
Tax Reform Foreign Currency Exchange Impact [Member] | Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (loss) gain				(50)
Argentine peso devaluation [Member] | Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (loss) gain		$ (82)	$ (51)	$ (68)

[1] 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.

[2] Includes net pre-tax exchange losses of $(82) million, $(51) million and $(68) million associated with the devaluation of the Argentine peso for the years ended December 31, 2020, 2019 and 2018, respectively.