Interest Income and Interest Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income
Loans	$ 43,758	$ 51,855	$ 49,032
Taxable securities	7,843	7,962	5,653
Non-taxable securities	1,184	1,329	1,595
Total investment securities	9,027	9,291	7,248
Trading assets - debt instruments	7,832	9,141	7,146
Federal funds sold and securities purchased under resale agreements	2,436	6,146	3,819
Securities borrowed	(302)	1,574	913
Deposits with banks	749	3,887	5,907
All other interest-earning assets	1,023	2,146	2,035
Total interest income	64,523	84,040	76,100
Interest expense
Interest bearing deposits	2,357	8,957	5,973
Federal funds purchased and securities loaned or sold under repurchase agreements	1,058	4,630	3,066
Short-term borrowings	372	1,248	1,144
Trading liabilities – debt and all other interest-bearing liabilities	195	2,585	2,387
Long-term debt	5,764	8,807	7,978
Beneficial interest issued by consolidated VIEs	214	568	493
Total interest expense	9,960	26,795	21,041
Net interest income	54,563	57,245	55,059
Provision for credit losses	17,480	5,585	4,871
Net interest income after provision for credit losses	$ 37,083	$ 51,660	$ 50,188