Derivative Instruments (Hedges of Net Investments in Foreign Operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivatives, Fair Value [Line Items]
Net Derivatives Gains (Losses) Deferred in AOCI	$ (25)	$ 21	$ 30	$ (13)
Currency Swap [Member]
Derivatives, Fair Value [Line Items]
Net Derivatives Gains (Losses) Deferred in AOCI	(3)	5	6	(5)
Foreign Exchange Forward [Member]
Derivatives, Fair Value [Line Items]
Net Derivatives Gains (Losses) Deferred in AOCI	$ (22)	$ 16	$ 24	$ (8)