Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 2,097	$ 1,735
Plus(Less): Related collateral	63	63
Total derivative assets	2,160	1,798
Interest rate
Credit Derivatives [Line Items]
Derivative assets before collateral	985	1,448
Foreign exchange
Credit Derivatives [Line Items]
Derivative assets before collateral	46	52
Commodity
Credit Derivatives [Line Items]
Derivative assets before collateral	1,046	178
Credit
Credit Derivatives [Line Items]
Derivative assets before collateral	0	(1)
Other
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 20	$ 58