Total Equity - Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Preferred Stock Dividends
Preferred stock dividends declared	$ 160	$ 160	$ 465	$ 440
Dividends declared per common share (USD per share)	$ 1.00	$ 0.925	$ 2.85	$ 2.625
Common stock dividends	$ 1,592	$ 1,492	$ 4,562	$ 4,259
Series A
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 337	$ 400	$ 996	$ 1,190
Preferred stock dividends declared	$ 15	$ 17	$ 44	$ 52
Series C
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 25	$ 25	$ 75	$ 75
Preferred stock dividends declared	$ 13	$ 13	$ 39	$ 39
Series E
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 455	$ 455	$ 1,351	$ 1,351
Preferred stock dividends declared	$ 16	$ 16	$ 47	$ 47
Series F
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 439	$ 439	$ 1,303	$ 1,308
Preferred stock dividends declared	$ 15	$ 15	$ 44	$ 44
Series I
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 407	$ 398	$ 1,209	$ 1,195
Preferred stock dividends declared	$ 16	$ 16	$ 48	$ 48
Series K
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 366	$ 366	$ 1,097	$ 1,097
Preferred stock dividends declared	$ 14	$ 15	$ 44	$ 44
Series L
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 305	$ 305	$ 914	$ 914
Preferred stock dividends declared	$ 6	$ 6	$ 18	$ 18
Series M
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 29	$ 30	$ 59	$ 59
Preferred stock dividends declared	$ 12	$ 12	$ 24	$ 24
Series N
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 1,957	$ 2,215	$ 5,875	$ 6,726
Preferred stock dividends declared	$ 6	$ 6	$ 18	$ 20
Series O
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 266	$ 266	$ 797	$ 797
Preferred stock dividends declared	$ 14	$ 13	$ 41	$ 41
Series P
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 406	$ 406	$ 1,219	$ 1,219
Preferred stock dividends declared	$ 16	$ 17	$ 48	$ 49
Series Q
Preferred Stock Dividends
Preferred stock dividend declared (USD per share)	$ 414	$ 345	$ 1,242	$ 345
Preferred stock dividends declared	$ 17	$ 14	$ 50	$ 14

Aggregate dividends declared during the period for each share of common stock outstanding.

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-SubTopic 405
-Topic 942
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477787/942-405-45-2

+ Details

Name:	us-gaap_DividendsCommonStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

+ References

+ Details

Name:	us-gaap_DividendsPreferredStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

Aggregate dividends declared during the period for each share of preferred stock outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_PreferredStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesAPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesCPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesEPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesFPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesIPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesKPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesLPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesMPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesNPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesOPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesPPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=ms_SeriesQPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: