Lines of business - Contribution of Segments to Overall Profitability (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019
Segment Reporting Information [Line Items]
Total fee and other revenue	$ 3,176	$ 3,332	$ 3,112	$ 6,508		$ 6,144
Net interest revenue (expense)	780	814	802	1,594		1,643
Provision for credit losses	143	169	(8)	312	[1]	(1)	[1]
Income from consolidated investment management funds, net of noncontrolling interests	950	980	1,017	1,930		1,963
Investment income (loss), net	54	(38)	10	16		36
Net income (loss) attributable to noncontrolling interests	15	(18)	4	(3)		14
Operating segments
Segment Reporting Information [Line Items]
Total fee and other revenue	3,215	3,312	3,118	6,527		6,166
Net interest revenue (expense)	780	814	802	1,594		1,643
Total revenue	3,995	4,126	3,920	8,121		7,809
Provision for credit losses	143	169	(8)	312		(1)
Noninterest expense	2,686	2,712	2,647	5,398		5,346
Income (loss) before taxes	$ 1,166	$ 1,245	$ 1,281	$ 2,411		$ 2,464
Pre-tax operating margin	29.00%	30.00%	33.00%	30.00%		32.00%
Average assets	$ 415,359	$ 385,278	$ 342,384	$ 400,318		$ 339,292
Operating segments | Investment Services
Segment Reporting Information [Line Items]
Total fee and other revenue	2,339	2,436	2,233	4,775		4,394
Net interest revenue (expense)	768	806	783	1,574		1,587
Total revenue	3,107	3,242	3,016	6,349		5,981
Provision for credit losses	145	149	(4)	294		4
Noninterest expense	1,989	1,987	1,963	3,976		3,944
Income (loss) before taxes	$ 973	$ 1,106	$ 1,057	$ 2,079		$ 2,033
Pre-tax operating margin	31.00%	34.00%	35.00%	33.00%		34.00%
Average assets	$ 335,288	$ 304,089	$ 264,781	$ 319,689		$ 260,432
Operating segments | Investment and Wealth Management
Segment Reporting Information [Line Items]
Total fee and other revenue	838	846	854	1,684		1,723
Net interest revenue (expense)	48	52	59	100		126
Total revenue	886	898	913	1,784		1,849
Provision for credit losses	7	9	(2)	16		(1)
Noninterest expense	658	695	655	1,353		1,324
Income (loss) before taxes	$ 221	$ 194	$ 260	$ 415		$ 526
Pre-tax operating margin	25.00%	22.00%	29.00%	23.00%		28.00%
Average assets	$ 30,327	$ 30,543	$ 29,793	$ 30,435		$ 30,819
Income from consolidated investment management funds, net of noncontrolling interests	39	(20)	6	19		22
Investment income (loss), net	54	(38)	10	16		36
Net income (loss) attributable to noncontrolling interests	15	(18)	4	(3)		14
Operating segments | Other
Segment Reporting Information [Line Items]
Total fee and other revenue	38	30	31	68		49
Net interest revenue (expense)	(36)	(44)	(40)	(80)		(70)
Total revenue	2	(14)	(9)	(12)		(21)
Provision for credit losses	(9)	11	(2)	2		(4)
Noninterest expense	39	30	29	69		78
Income (loss) before taxes	(28)	(55)	(36)	(83)		(95)
Average assets	$ 49,744	$ 50,646	$ 47,810	$ 50,194		$ 48,041

[1] In the first quarter of 2020, we adopted new accounting guidance included in ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments, on a prospective basis. See Note 2 of the Notes to Consolidated Financial Statements for additional information.