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Equity Method Investments (Narratives) (Details)
In Millions, unless otherwise specified |
12 Months Ended | 0 Months Ended | 12 Months Ended | 12 Months Ended | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2012
USD ($)
|
Dec. 31, 2011
USD ($)
|
Dec. 31, 2010
USD ($)
|
Dec. 31, 2012
China International Capital Corporation Limited
USD ($)
|
Dec. 31, 2011
China International Capital Corporation Limited
USD ($)
|
Dec. 31, 2010
China International Capital Corporation Limited
USD ($)
|
Nov. 24, 2011
MUMSS
USD ($)
|
Apr. 22, 2011
MUMSS
USD ($)
|
May 01, 2010
MUMSS
USD ($)
|
May 01, 2010
MUMSS
JPY (¥)
|
Dec. 31, 2012
MUMSS
USD ($)
|
Dec. 31, 2011
MUMSS
USD ($)
|
Dec. 31, 2010
MUMSS
USD ($)
|
Dec. 31, 2012
MSMS
|
Dec. 31, 2011
FrontPoint
USD ($)
|
Dec. 31, 2011
Morgan Stanley Huaxin Securities Company Limited
USD ($)
|
Dec. 31, 2012
Structured Transactions and Other Investments
USD ($)
|
Dec. 31, 2011
Structured Transactions and Other Investments
USD ($)
|
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| Schedule of Equity Method Investments [Line Items] | |||||||||||||||||||||||||
| Equity method investment | $ 4,682 | $ 4,524 | $ 1,428 | [1] | $ 1,444 | [1] | $ 2,800 | $ 2,500 | |||||||||||||||||
| Income (loss) from equity method investments | (23) | (995) | (37) | 152 | (783) | (62) | |||||||||||||||||||
| Percent ownership | 34.30% | 40.00% | |||||||||||||||||||||||
| Gain (loss) on sale of equity method investments | 0 | 0 | 668 | 0 | 0 | 668 | |||||||||||||||||||
| Cash contribution received from partner(s) of the joint venture | 247 | 23,000 | |||||||||||||||||||||||
| Economic interest held by joint venture partners | 60.00% | 60.00% | |||||||||||||||||||||||
| Voting interest in joint venture | 40.00% | 51.00% | |||||||||||||||||||||||
| Voting interest held by noncontrolling interest | 60.00% | 49.00% | |||||||||||||||||||||||
| Proceeds from transfer of fixed income trading positions | 659 | ||||||||||||||||||||||||
| Capital injection by joint venture partner due to losses | 259 | 370 | |||||||||||||||||||||||
| Capital injection to joint venture due to factors other than losses | 129 | ||||||||||||||||||||||||
| Capital injection by joint venture partner due to factors other than losses | 195 | ||||||||||||||||||||||||
| Increase in carrying amount of the equity method investment | 251 | ||||||||||||||||||||||||
| Share of increase (increase) in the net asset value, percent | 40.00% | ||||||||||||||||||||||||
| Increase to paid-in capital | 146 | ||||||||||||||||||||||||
| Loss on write-down of minority interest in equity method investment | 27 | ||||||||||||||||||||||||
| Impairment losses | 4 | [2] | 7 | 3 | |||||||||||||||||||||
| Transaction cost in business acquisition | $ 130 | ||||||||||||||||||||||||
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