Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 2,504	$ 1,735
Plus(Less): Related collateral	49	63
Total derivative assets	2,553	1,798
Interest rate
Credit Derivatives [Line Items]
Derivative assets before collateral	838	1,448
Foreign exchange
Credit Derivatives [Line Items]
Derivative assets before collateral	38	52
Commodity
Credit Derivatives [Line Items]
Derivative assets before collateral	1,606	178
Credit
Credit Derivatives [Line Items]
Derivative assets before collateral	0	(1)
Other
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 22	$ 58