Supplementary Information Foreign Currency Exchange Gain (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (losses) gains - net	$ (61)	$ (27)
Foreign Currency Transaction (Loss) Gain Tax (Expense) Benefit	(17)	(6)
Foreign Currency Transaction (Loss) Gain After Tax	(78)	(33)
Subsidiary Monetary Position
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (losses) gains - net	(226)	(10)
Foreign Currency Transaction (Loss) Gain Tax (Expense) Benefit	23	(10)
Foreign Currency Transaction (Loss) Gain After Tax	(203)	(20)
Hedging Program [Member]
Foreign Currency Exchange Gain (Loss) [Line Items]
Pre-tax exchange (losses) gains - net	165	(17)
Foreign Currency Transaction (Loss) Gain Tax (Expense) Benefit	(40)	4
Foreign Currency Transaction (Loss) Gain After Tax	$ 125	$ (13)