Commitments, Guarantees and Contingencies - Commitments (Details) $ in Millions	Sep. 30, 2022 USD ($)
Commitment, Fiscal Year Maturity
Less than 1 (year)	$ 96,857
1-3 (years)	41,482
3-5 (years)	57,322
Over 5 (years)	12,828
Total	208,489
Forward-starting secured financing receivables
Commitment, Fiscal Year Maturity
Less than 1 (year)	62,091
1-3 (years)	0
3-5 (years)	0
Over 5 (years)	0
Total	62,091
Forward-starting secured financing receivables settled within three business days	45,666
Central counterparty
Commitment, Fiscal Year Maturity
Less than 1 (year)	300
1-3 (years)	0
3-5 (years)	0
Over 5 (years)	4,909
Total	5,209
Underwriting
Commitment, Fiscal Year Maturity
Less than 1 (year)	2,350
1-3 (years)	0
3-5 (years)	0
Over 5 (years)	0
Total	2,350
Investment activities
Commitment, Fiscal Year Maturity
Less than 1 (year)	1,479
1-3 (years)	169
3-5 (years)	65
Over 5 (years)	351
Total	2,064
Letters of credit and other financial guarantees
Commitment, Fiscal Year Maturity
Less than 1 (year)	168
1-3 (years)	0
3-5 (years)	0
Over 5 (years)	2
Total	170
Corporate
Commitment, Fiscal Year Maturity
Less than 1 (year)	11,654
1-3 (years)	29,955
3-5 (years)	54,877
Over 5 (years)	6,105
Total	102,591
Lending commitments participated to third parties	7,877
Secured lending facilities
Commitment, Fiscal Year Maturity
Less than 1 (year)	6,297
1-3 (years)	6,007
3-5 (years)	1,814
Over 5 (years)	775
Total	14,893
Commercial and Residential real estate
Commitment, Fiscal Year Maturity
Less than 1 (year)	103
1-3 (years)	339
3-5 (years)	18
Over 5 (years)	296
Total	756
Securities-based lending and Other
Commitment, Fiscal Year Maturity
Less than 1 (year)	12,415
1-3 (years)	5,012
3-5 (years)	548
Over 5 (years)	390
Total	$ 18,365

Commitments participated to third parties.

No definition available.

Name:	ms_CommitmentsParticipatedToThirdParties
Namespace Prefix:	ms_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum amount of other commitment maturing in the next three business days following the latest fiscal year for commitments not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in this taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

Name:	ms_OtherCommitmentDueInNextThreeDays
Namespace Prefix:	ms_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment classified as other to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

Name:	us-gaap_OtherCommitmentDueAfterFifthYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment classified as other to be paid in fourth and fifth fiscal years following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

Name:	us-gaap_OtherCommitmentDueInFourthAndFifthYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment classified as other to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

Name:	us-gaap_OtherCommitmentDueInNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of commitment classified as other to be paid in second and third fiscal years following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

No definition available.

+ Details

Name:	us-gaap_OtherCommitmentDueInSecondAndThirdYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_OtherCommitmentFiscalYearMaturityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_OtherCommitmentsAxis=ms_CommitmentsForwardStartingReverseRepurchaseAgreementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=ms_CentralCounterpartyCommitmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=ms_FirmCommitmentContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=ms_CommitmentsInvestmentActivitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherCommitmentsAxis=ms_CommitmentsLettersOfCreditAndOtherFinancialGuaranteesObtainedToSatisfyCollateralRequirementsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=ms_SecuredLendingFacilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_RealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=ms_SecuritiesBasedLendingandOtherLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: