Consolidated Comprehensive Income Statements (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 4,168	$ 1,780
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(219)	(132)
Change in net unrealized gains (losses) on available-for-sale securities	(776)	1,325
Pension and other	5	25
Change in net debt valuation adjustment	137	3,803
Total other comprehensive income (loss)	(853)	5,021
Comprehensive income	3,315	6,801
Net income applicable to noncontrolling interests	48	82
Other comprehensive income (loss) applicable to noncontrolling interests	(61)	138
Comprehensive income applicable to Morgan Stanley	$ 3,328	$ 6,581