Business Segments - Segment Operating Results (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Non-interest revenues	$ 32,184	$ 32,849	$ 29,798
Net interest income	4,362	3,767	2,932
Total net revenues	36,546	36,616	32,730
Provision for credit losses	1,065	674	657
Operating expenses	24,898	23,461	20,941
Pre-tax earnings	10,583	12,481	11,132
Net earnings	8,466	10,459	4,286
Net earnings to common	7,897	9,860	3,685
Average common equity	$ 79,094	$ 73,985	$ 74,721
Return on average common equity	10.00%	13.30%	4.90%
Investment Banking [Member]
Segment Reporting Information [Line Items]
Non-interest revenues	$ 7,079	$ 7,856	$ 7,158
Net interest income	520	322	301
Total net revenues	7,599	8,178	7,459
Provision for credit losses	333	124	34
Operating expenses	4,685	4,473	3,613
Pre-tax earnings	2,581	3,581	3,812
Net earnings	2,065	3,001	1,468
Net earnings to common	1,996	2,924	1,394
Average common equity	$ 11,167	$ 8,737	$ 8,753
Return on average common equity	17.90%	33.50%	15.90%
Global Markets [Member]
Segment Reporting Information [Line Items]
Non-interest revenues	$ 13,109	$ 12,831	$ 10,853
Net interest income	1,670	1,607	1,442
Total net revenues	14,779	14,438	12,295
Provision for credit losses	35	52	178
Operating expenses	10,851	10,585	9,981
Pre-tax earnings	3,893	3,801	2,136
Net earnings	3,114	3,185	823
Net earnings to common	2,729	2,796	397
Average common equity	$ 40,060	$ 41,237	$ 44,448
Return on average common equity	6.80%	6.80%	0.90%
Asset Management [Member]
Segment Reporting Information [Line Items]
Non-interest revenues	$ 8,454	$ 8,353	$ 8,491
Net interest income	511	482	39
Total net revenues	8,965	8,835	8,530
Provision for credit losses	274	160	322
Operating expenses	4,817	4,179	3,773
Pre-tax earnings	3,874	4,496	4,435
Net earnings	3,099	3,767	1,707
Net earnings to common	3,013	3,668	1,639
Average common equity	$ 21,575	$ 19,061	$ 16,904
Return on average common equity	14.00%	19.20%	9.70%
Consumer & Wealth Management [Member]
Segment Reporting Information [Line Items]
Non-interest revenues	$ 3,542	$ 3,809	$ 3,296
Net interest income	1,661	1,356	1,150
Total net revenues	5,203	5,165	4,446
Provision for credit losses	423	338	123
Operating expenses	4,545	4,224	3,574
Pre-tax earnings	235	603	749
Net earnings	188	506	288
Net earnings to common	159	472	255
Average common equity	$ 6,292	$ 4,950	$ 4,616
Return on average common equity	2.50%	9.50%	5.50%