Segment, Geographic and Revenue Information - Revenue Recognized from Prior Services (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Segment Reporting [Abstract]
Non-interest revenues	$ 1,005	$ 541

Revenue recognized in the reporting period from performance obligations satisfied (or partially satisfied) in previous periods.

No definition available.

Name:	ms_RevenueFromContractWithCustomerPerformanceObligationsFullyOrPartiallySatisfiedInPriorPeriods
Namespace Prefix:	ms_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration