Parent Company (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Non-interest revenues
Other									$ 1,430	$ 1,360	$ 1,457
Total non-interest revenues									34,936	32,675	30,427
Interest income									12,084	10,606	8,563
Interest expense									3,464	2,943	2,112
Total revenues net of interest expense	$ 11,365	$ 10,989	$ 10,838	$ 10,364	$ 10,474	$ 10,144	$ 10,002	$ 9,718	43,556	40,338	36,878
Expenses
Salaries and employee benefits									5,911	5,250	5,258
Other									5,868	5,671	5,634
Total Expenses									31,554	28,864	26,693
Pretax income	1,986	2,266	2,219	1,958	1,831	2,118	2,091	2,082	8,429	8,122	7,425
Income tax provision (benefit)									1,670	1,201	4,677
Net income	$ 1,693	$ 1,755	$ 1,761	$ 1,550	$ 2,010	$ 1,654	$ 1,623	$ 1,634	6,759	6,921	2,748
Parent Company [Member]
Non-interest revenues
Other									598	426	358
Total non-interest revenues									598	426	358
Interest income									692	422	258
Interest expense									902	615	493
Total revenues net of interest expense									388	233	123
Expenses
Salaries and employee benefits									366	336	362
Other									816	607	553
Total Expenses									1,182	943	915
Pretax income									(794)	(710)	(792)
Income tax provision (benefit)									(282)	(179)	(354)
Net loss before equity in net income of subsidiaries and affiliates									(512)	(531)	(438)
Equity in net income of subsidiaries and affiliates									7,271	7,452	3,186
Net income									$ 6,759	$ 6,921	$ 2,748