Noninterest Revenue and Noninterest Expense - Principal Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Non interest Revenue [Line Items]
Total trading revenue	$ 12,408	$ 11,088	$ 11,309
Private equity gains	(349)	259	257
Principal transactions	12,059	11,347	11,566
Interest rate
Schedule of Non interest Revenue [Line Items]
Total trading revenue	1,961	2,479	2,325
Credit
Schedule of Non interest Revenue [Line Items]
Total trading revenue	1,395	1,329	2,096
Foreign exchange
Schedule of Non interest Revenue [Line Items]
Total trading revenue	3,222	2,746	2,827
Equity
Schedule of Non interest Revenue [Line Items]
Total trading revenue	4,924	3,873	2,994
Commodity
Schedule of Non interest Revenue [Line Items]
Total trading revenue	$ 906	$ 661	$ 1,067