Derivatives - Derivative Instruments Included in the Consolidated Balance Sheets (Parenthetical) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value
Amount of variation margin payment applied to derivative asset contracts	$ 748	$ 249
Amount of variation margin payment applied to derivative liability contracts	528	$ 23
Nondesignated | Customer Accommodation | Interest Rate Contract
Derivatives, Fair Value
Amount of variation margin payment applied to derivative asset contracts	36
Amount of variation margin payment applied to derivative liability contracts	$ 621