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		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Total interest on medium- and long-term debt	[1]	$ 19	$ 51	$ 59	$ 102
Swaps - fair value - receive fixed/pay floating | Risk management purposes | Interest rate swap
Interest rate contract: Hedge items interest expense		28	26	58	52
Interest rate contracts: Derivatives designated as hedging instruments net interest income		$ (12)	$ 0	$ (18)	$ 1

[1] Includes the effects of hedging.