Segment, Geographic and Revenue Information - Selected Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information
Investment banking	$ 1,373	$ 3,013	$ 4,281	$ 8,413
Trading	3,331	2,861	10,911	10,416
Investments	(168)	45	(70)	744
Commissions and fees	1,133	1,280	3,769	4,214
Asset management	4,744	5,201	14,775	14,572
Other	63	290	245	916
Total non-interest revenues	10,476	12,690	33,911	39,275
Interest income	6,101	2,351	12,363	7,000
Interest expense	3,591	288	5,355	1,044
Net interest	2,510	2,063	7,008	5,956
Net revenues	12,986	14,753	40,919	45,231
Provision for credit losses	35	24	193	(1)
Compensation and benefits	5,614	5,920	17,438	19,141
Non-compensation expenses	3,949	3,935	11,993	11,307
Total non-interest expenses	9,563	9,855	29,431	30,448
Income before provision for income taxes	3,388	4,874	11,295	14,784
Provision for income taxes	726	1,150	2,382	3,380
Net income	2,662	3,724	8,913	11,404
Net income (loss) applicable to noncontrolling interests	30	17	120	66
Net income applicable to Morgan Stanley	2,632	3,707	8,793	11,338
I/E
Segment Reporting Information
Investment banking	(18)	(22)	(56)	(65)
Trading	10	21	43	63
Investments	0	0	0	0
Commissions and fees	(58)	(88)	(210)	(272)
Asset management	(54)	(42)	(153)	(117)
Other	(4)	(1)	(10)	(7)
Total non-interest revenues	(124)	(132)	(386)	(398)
Interest income	(432)	(69)	(676)	(133)
Interest expense	(437)	(71)	(683)	(140)
Net interest	5	2	7	7
Net revenues	(119)	(130)	(379)	(391)
Provision for credit losses	0	0	0	0
Compensation and benefits	0	0	0	0
Non-compensation expenses	(116)	(131)	(371)	(397)
Total non-interest expenses	(116)	(131)	(371)	(397)
Income before provision for income taxes	(3)	1	(8)	6
Provision for income taxes	(1)	0	(2)	1
Net income	(2)	1	(6)	5
Net income (loss) applicable to noncontrolling interests	0	0	0	0
Net income applicable to Morgan Stanley	(2)	1	(6)	5
IS | Operating Segments
Segment Reporting Information
Investment banking	1,277	2,849	3,983	7,838
Trading	3,330	2,897	11,511	10,048
Investments	(73)	52	(69)	199
Commissions and fees	648	664	2,110	2,216
Asset management	140	145	442	432
Other	(25)	172	(131)	467
Total non-interest revenues	5,297	6,779	17,846	21,200
Interest income	3,889	948	6,797	2,791
Interest expense	3,369	232	5,050	827
Net interest	520	716	1,747	1,964
Net revenues	5,817	7,495	19,593	23,164
Provision for credit losses	24	24	150	1
Compensation and benefits	1,948	2,248	6,602	7,795
Non-compensation expenses	2,219	2,250	6,874	6,526
Total non-interest expenses	4,167	4,498	13,476	14,321
Income before provision for income taxes	1,626	2,973	5,967	8,842
Provision for income taxes	305	713	1,235	2,023
Net income	1,321	2,260	4,732	6,819
Net income (loss) applicable to noncontrolling interests	47	31	146	85
Net income applicable to Morgan Stanley	1,274	2,229	4,586	6,734
WM | Operating Segments
Segment Reporting Information
Investment banking	114	186	354	640
Trading	(41)	(58)	(681)	323
Investments	18	8	45	24
Commissions and fees	543	704	1,869	2,269
Asset management	3,389	3,628	10,525	10,266
Other	93	119	388	479
Total non-interest revenues	4,116	4,587	12,500	14,001
Interest income	2,626	1,464	6,208	4,316
Interest expense	622	116	917	328
Net interest	2,004	1,348	5,291	3,988
Net revenues	6,120	5,935	17,791	17,989
Provision for credit losses	11	0	43	(2)
Compensation and benefits	3,171	3,159	9,191	9,604
Non-compensation expenses	1,289	1,246	3,814	3,621
Total non-interest expenses	4,460	4,405	13,005	13,225
Income before provision for income taxes	1,649	1,530	4,743	4,766
Provision for income taxes	396	373	1,028	1,103
Net income	1,253	1,157	3,715	3,663
Net income (loss) applicable to noncontrolling interests	0	0	0	0
Net income applicable to Morgan Stanley	1,253	1,157	3,715	3,663
IM | Operating Segments
Segment Reporting Information
Investment banking	0	0	0	0
Trading	32	1	38	(18)
Investments	(113)	(15)	(46)	521
Commissions and fees	0	0	0	1
Asset management	1,269	1,470	3,961	3,991
Other	(1)	0	(2)	(23)
Total non-interest revenues	1,187	1,456	3,951	4,472
Interest income	18	8	34	26
Interest expense	37	11	71	29
Net interest	(19)	(3)	(37)	(3)
Net revenues	1,168	1,453	3,914	4,469
Provision for credit losses	0	0	0	0
Compensation and benefits	495	513	1,645	1,742
Non-compensation expenses	557	570	1,676	1,557
Total non-interest expenses	1,052	1,083	3,321	3,299
Income before provision for income taxes	116	370	593	1,170
Provision for income taxes	26	64	121	253
Net income	90	306	472	917
Net income (loss) applicable to noncontrolling interests	(17)	(14)	(26)	(19)
Net income applicable to Morgan Stanley	$ 107	$ 320	$ 498	$ 936