Derivatives and Hedging Activities - Fair Value of Derivative Assets by Type (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 2,262	$ 987
Less: Related collateral	169	207
Total derivative assets	2,093	780
Interest rate
Credit Derivatives [Line Items]
Derivative assets before collateral	1,860	848
Foreign exchange
Credit Derivatives [Line Items]
Derivative assets before collateral	49	30
Commodity
Credit Derivatives [Line Items]
Derivative assets before collateral	270	95
Credit
Credit Derivatives [Line Items]
Derivative assets before collateral	0	0
Other
Credit Derivatives [Line Items]
Derivative assets before collateral	$ 83	$ 14