Cash Contributed by Partner

Name:	ms_CashContributedByPartner
Namespace Prefix:	ms
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Equity Method Investment, Percentage of Voting Interest

+ Details

Name:	ms_EquityMethodInvestmentPercentageOfVotingInterest
Namespace Prefix:	ms
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity Method Investment Transaction, Fair Value of Consideration

+ Details

Name:	ms_EquityMethodTransactionFairValueOfConsideration
Namespace Prefix:	ms
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Increase Decrease In Equity Method Investment Ownership Percentage

+ Details

Name:	ms_IncreaseDecreaseInEquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	ms
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Increase decrease in equity method of investment, carrying value.

+ Details

Name:	ms_IncreaseDecreaseInEquityMethodOfInvestmentCarryingValue
Namespace Prefix:	ms
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Increase Decrease In Paid In Capital

+ Details

Name:	ms_IncreaseDecreaseInPaidInCapital
Namespace Prefix:	ms
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Joint Venture Interest.

+ Details

Name:	ms_JointVentureInterest
Namespace Prefix:	ms
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss On Write-Down Of Minority Interest In Equity Method Investment

+ Details

Name:	ms_LossOnWriteDownOfMinorityInterestInEquityMethodInvestment
Namespace Prefix:	ms
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Noncontrolling Interest, Ownership Percentage

+ Details

Name:	ms_NoncontrollingInterestOwnershipPercentage
Namespace Prefix:	ms
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Noncontrolling Interest, Percentage of Voting Interest

+ Details

Name:	ms_NoncontrollingInterestPercentageOfVotingInterest
Namespace Prefix:	ms
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 159
-Paragraph 18
-Subparagraph f
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 20
-Subparagraph a (1)
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6382870&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 19
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 18
-Paragraph 6
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 28
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 11
-Article 7

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 5
-Section 03
-Paragraph 9

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.12)
-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

+ Details

Name:	us-gaap_IncomeLossFromEquityMethodInvestments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 17
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireInterestInJointVenture
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Equity Method Investments (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended
	Apr. 22, 2011	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011 Morgan Stanley And Huaxin Securities Joint Venture [Member]	Jun. 30, 2011 Mitsubishi UFJ Morgan Stanley Securities Co., Ltd [Member]	Jun. 30, 2011 Mitsubishi UFJ Morgan Stanley Securities Co., Ltd [Member]	Jun. 30, 2011 MSMS [Member]	Jun. 30, 2011 FrontPoint [Member]	Jun. 30, 2011 MUMSS [Member]
Costs incurred related to formation of joint venture				$ 130
Joint venture interest		Huaxin Securities holds a two-thirds interest in the joint venture while the Company owns a one-third interest
Percent ownership					40.00%	40.00%
Economic interest owned by MUFG						60.00%
Voting interest in joint venture						40.00%	51.00%
Voting interest held by MUFG						60.00%	49.00%
Gain (loss) on equity method investees		725	(78)		(17)	(672)
Total consideration received		659
Cash contribution by MUFG	370
Increase in carrying amount of the equity method investment									148
Increase in net asset value									40.00%
Increase in paid in capital									86
Loss on write-down of minority interest in equity method investment								$ 20