Fair Values - Financial Instruments Not Measured at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Financial assets
Securities borrowed	$ 150,995	$ 129,713
Customer and other receivables	94,804	96,018
Loans	182,247	174,302
Financial liabilities
Deposits	360,840	347,574
Securities sold under agreements to repurchase	60,068	62,188
Securities loaned	14,222	12,299
Other secured financings	8,808	10,041
Customer and other payables	243,609	228,685
Borrowings	229,817	233,127
Carrying Value
Financial assets
Cash and cash equivalents	136,086	127,725
Investment securities—HTM	80,439	80,168
Securities purchased under agreements to resell	127,765	119,992
Securities borrowed	150,995	129,713
Customer and other receivables	90,134	91,664
Loans	196,260	188,134
Other assets	509	528
Financial liabilities
Deposits	358,827	345,634
Securities sold under agreements to repurchase	59,104	61,397
Securities loaned	14,222	12,299
Other secured financings	4,057	4,908
Customer and other payables	243,281	228,631
Borrowings	153,854	156,787
Additional Disclosures
Lending commitments	141,421	133,519
Fair Value
Financial assets
Cash and cash equivalents	136,086	127,725
Investment securities—HTM	75,776	79,882
Securities purchased under agreements to resell	127,729	119,997
Securities borrowed	150,995	129,713
Customer and other receivables	89,870	91,533
Loans	194,409	189,490
Other assets	509	528
Financial liabilities
Deposits	358,993	345,911
Securities sold under agreements to repurchase	59,089	61,419
Securities loaned	14,223	12,296
Other secured financings	4,059	4,910
Customer and other payables	243,281	228,631
Borrowings	155,447	162,158
Additional Disclosures
Lending commitments	1,676	1,360
Fair Value | Level 1
Financial assets
Cash and cash equivalents	136,086	127,725
Investment securities—HTM	29,099	29,454
Securities purchased under agreements to resell	0	0
Securities borrowed	0	0
Customer and other receivables	0	0
Loans	0	0
Other assets	0	0
Financial liabilities
Deposits	0	0
Securities sold under agreements to repurchase	0	0
Securities loaned	0	0
Other secured financings	0	0
Customer and other payables	0	0
Borrowings	0	0
Additional Disclosures
Lending commitments	0	0
Fair Value | Level 2
Financial assets
Cash and cash equivalents	0	0
Investment securities—HTM	45,633	49,352
Securities purchased under agreements to resell	125,543	117,922
Securities borrowed	150,995	129,713
Customer and other receivables	86,417	88,091
Loans	24,140	25,706
Other assets	509	528
Financial liabilities
Deposits	358,993	345,911
Securities sold under agreements to repurchase	59,089	61,419
Securities loaned	14,223	12,296
Other secured financings	4,059	4,910
Customer and other payables	243,281	228,631
Borrowings	155,443	162,154
Additional Disclosures
Lending commitments	1,162	890
Fair Value | Level 3
Financial assets
Cash and cash equivalents	0	0
Investment securities—HTM	1,044	1,076
Securities purchased under agreements to resell	2,186	2,075
Securities borrowed	0	0
Customer and other receivables	3,453	3,442
Loans	170,269	163,784
Other assets	0	0
Financial liabilities
Deposits	0	0
Securities sold under agreements to repurchase	0	0
Securities loaned	0	0
Other secured financings	0	0
Customer and other payables	0	0
Borrowings	4	4
Additional Disclosures
Lending commitments	$ 514	$ 470