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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Total interest on medium- and long-term debt	[1]	$ 50	$ 40	$ 152	$ 97
Swaps - fair value - receive fixed/pay floating | Risk management purposes | Interest rate swap
Interest rate contract: Hedge items interest expense		28	21	80	51
Interest rate contracts: Derivatives designated as hedging instruments net interest income		$ (2)	$ (1)	$ (1)	$ (7)

[1] Includes the effects of hedging.