Derivatives - Derivative Instruments Included in the Condensed Consolidated Balance Sheets (Parenthetical) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Amount of variation margin payment applied to derivative asset contracts	$ 1,200	$ 623
Amount of variation margin payment applied to derivative liability contracts	1,300	488
Nondesignated | Customer Accommodation | Interest Rate Contract
Derivatives, Fair Value [Line Items]
Amount of variation margin payment applied to derivative asset contracts	50	40
Amount of variation margin payment applied to derivative liability contracts	$ 1,288	$ 493