Derivative And Credit-Related Financial Instruments Derivative and Credit-Related Financial Instruments (Schedule of the Effects of Fair Value Hedging on the Consolidated Statements of Comprehensive Income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Total interest on medium- and long-term debt	[1]	$ 11	$ 50	$ 70	$ 152
Swaps - fair value - receive fixed/pay floating | Risk management purposes | Interest rate swap
Interest rate contract: Hedge items interest expense		26	28	84	80
Interest rate contracts: Derivatives designated as hedging instruments net interest income		$ (16)	$ (2)	$ (34)	$ (1)

[1] Includes the effects of hedging.