Consolidated Investment Entities (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of changes in Level 3 assets held by consolidated investment entities
Transfers out of Level 3	$ (146)	$ (3,900)
Corporate debt securities | Consolidated Investment Entities
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	4	6
Cumulative effect of accounting change			15
Purchases, Net-Assets		3
Sales, Net-Assets		(2)
Settlements, Net-Assets	(1)	(1)
Purchases, Sales, Issues and Settlements, Net			(9)
Transfers out of Level 3		(2)
Balance, at the end of the period	3	4	6
Common Stocks | Consolidated Investment Entities
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	13	11
Total Gains (Losses) Included in Net Income-Assets	(1)	6	4
Purchases, Net-Assets	7
Sales, Net-Assets	(5)	(4)
Transfers into Level 3	15	29	7
Transfers out of Level 3	(15)	(29)
Balance, at the end of the period	14	13	11
Changes in unrealized gains/ (losses) included in income relating to assets held		3	4
Other structured investments | Consolidated Investment Entities
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period		22
Cumulative effect of accounting change			5
Total Gains (Losses) Included in Net Income-Assets		(1)	1
Purchases, Net-Assets		3
Purchases, Sales, Issues and Settlements, Net			12
Transfers into Level 3			4
Transfers out of Level 3		(24)
Balance, at the end of the period			22
Changes in unrealized gains/ (losses) included in income relating to assets held			1
Syndicated loans | Consolidated Investment Entities
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	342
Total Gains (Losses) Included in Net Income-Assets	11	(12)
Purchases, Net-Assets	91	208
Sales, Net-Assets	(14)	(40)
Settlements, Net-Assets	(87)	(137)
Transfers into Level 3	255	615
Transfers out of Level 3	(396)	(292)
Balance, at the end of the period	202	342
Changes in unrealized gains/ (losses) included in income relating to assets held		(5)
Other assets | Consolidated Investment Entities
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	1,108	887	831
Total Gains (Losses) Included in Net Income-Assets	(78)	13	67
Total Gains (Losses) Included in Net Income-Assets and included in Other Revenues in the Consolidated Statement of Operations			69
Total Gains (Losses) Included in Net Income-Assets and included in Net Investment Income in the Consolidated Statement of Operations			(2)
Total Gains (Losses) Included in Other Comprehensive Income-Assets	28	(10)	(35)
Purchases, Net-Assets	328	299
Sales, Net-Assets	(172)	(81)
Settlements, Net-Assets		1
Purchases, Sales, Issues and Settlements, Net			24
Transfers into Level 3		7
Transfers out of Level 3		(8)
Balance, at the end of the period	1,214	1,108	887
Changes in unrealized gains/ (losses) included in income relating to assets held	(98)	19	40
Changes in unrealized gains/ (losses) included in income relating to assets held-other revenue		20	42
Changes in unrealized gains/ (losses) included in income relating to assets held-investment income		(1)	(2)
Debt | Consolidated Investment Entities
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period	(4,712)	(5,171)
Cumulative effect of accounting change			(4,962)
Total Gains (Losses) Included in Net Income-Liabilities	(316)	(89)	(339)
Issues, Net-Liabilities		(27)
Settlements, Net-Liabilities	578	575
Purchases, Sales, Issues and Settlements, Net-Liabilities			130
Balance, at the end of the period	(4,450)	(4,712)	(5,171)
Changes in unrealized gains/ (losses) included in income relating to liabilities held	$ (315)	$ (64)	$ (339)