Trading Activities, Net Interest Income and Net Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net Interest Income and Net Gains (Losses) on Trading Activities [Line Items]
Equity Securities, interest income	$ 236	$ 221	$ 446	$ 452
Loans held for sale, interest income	20	48	44	72
Total interest income	16,986	16,015	33,989	31,362
Net interest income	12,095	12,541	24,406	24,779
Debt securities, net gains (losses)	401	(140)	1,089	(639)
Equity securities, net gains (losses)	1,236	(635)	3,303	(1,104)
Loans held for sale, net gain (losses)	(4)	7	10	15
Derivatives (3)	(1,404)	959	(3,816)	2,162
Net gains from trading activities	229	191	586	434
Total trading-related net interest and noninterest income	1,005	879	2,157	1,774
Held for trading [Member]
Net Interest Income and Net Gains (Losses) on Trading Activities [Line Items]
Debt Securities, interest income	740	689	1,533	1,320
Equity Securities, interest income	143	128	258	269
Loans held for sale, interest income	20	15	43	23
Total interest income	903	832	1,834	1,612
Total interest expense	127	144	263	272
Net interest income	$ 776	$ 688	$ 1,571	$ 1,340