Noninterest Revenue and Noninterest Expense - Principal Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Non interest Revenue [Line Items]
Total trading revenue	$ 17,840	$ 14,268	$ 12,408
Private equity gains/ (losses)	181	(250)	(349)
Principal transactions	18,021	14,018	12,059
Interest rate
Schedule of Non interest Revenue [Line Items]
Total trading revenue	2,575	2,739	1,844
Credit
Schedule of Non interest Revenue [Line Items]
Total trading revenue	2,753	1,628	1,625
Foreign exchange
Schedule of Non interest Revenue [Line Items]
Total trading revenue	4,253	3,179	3,222
Equity
Schedule of Non interest Revenue [Line Items]
Total trading revenue	6,171	5,589	4,822
Commodity
Schedule of Non interest Revenue [Line Items]
Total trading revenue	$ 2,088	$ 1,133	$ 895