Derivative Financial Instruments and Hedging Activities - Recognized in the Balance Sheet (Details) - Derivatives Designated as Hedges [Member] - Fair Value Hedging [Member] - Unsecured Debt [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Carrying Amount of Hedged Items	$ 20,397	$ 17,923
Cumulative Amount of Fair Value Hedging Adjustments	(77)	459
Discontinued hedge cumulative amount of fair value hedging adjustments	$ 69	$ 247