Consolidated Investment Entities (Details 2) (Consolidated Investment Entities, USD $)	6 Months Ended	3 Months Ended	6 Months Ended				3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 Corporate debt securities	Jun. 30, 2013 Corporate debt securities	Jun. 30, 2012 Corporate debt securities	Mar. 31, 2012 Corporate debt securities	Dec. 31, 2011 Corporate debt securities	Jun. 30, 2013 Common Stocks	Jun. 30, 2012 Common Stocks	Jun. 30, 2013 Common Stocks	Jun. 30, 2012 Common Stocks	Jun. 30, 2013 Syndicated loans	Jun. 30, 2012 Syndicated loans	Jun. 30, 2013 Syndicated loans	Jun. 30, 2012 Syndicated loans	Jun. 30, 2013 Other assets	Jun. 30, 2012 Other assets	Jun. 30, 2013 Other assets	Jun. 30, 2012 Other assets	Jun. 30, 2013 Debt	Jun. 30, 2012 Debt	Jun. 30, 2013 Debt	Jun. 30, 2012 Debt
Summary of changes in Level 3 assets held by consolidated investment entities
Balance, at the beginning of the period		$ 3,000,000	$ 3,000,000	$ 4,000,000	$ 4,000,000	$ 4,000,000	$ 8,000,000	$ 8,000,000	$ 14,000,000	$ 13,000,000	$ 205,000,000	$ 195,000,000	$ 202,000,000	$ 342,000,000	$ 1,176,000,000	$ 1,035,000,000	$ 1,214,000,000	$ 1,108,000,000
Balance, at the beginning of the period																			(4,595,000,000)	(4,769,000,000)	(4,450,000,000)	(4,712,000,000)
Total Gains (Losses) Included in Net Income-Assets							1,000,000		1,000,000	(1,000,000)	1,000,000	1,000,000	1,000,000	4,000,000	8,000,000	(25,000,000)	2,000,000	(52,000,000)
Total Gains (Losses) Included in Net Income-Liabilities																			(61,000,000)	(16,000,000)	(88,000,000)	(141,000,000)
Total Gains (Losses) Included in Other Comprehensive loss-Assets															3,000,000	(19,000,000)	(74,000,000)	13,000,000
Purchases, Net-Assets		1,000,000	1,000,000							6,000,000	117,000,000	27,000,000	193,000,000	34,000,000	144,000,000	96,000,000	195,000,000	108,000,000
Sales, Net-Assets		(1,000,000)	(1,000,000)				(3,000,000)	(2,000,000)	(3,000,000)	(4,000,000)	(26,000,000)	(2,000,000)	(44,000,000)	(7,000,000)	(17,000,000)	(7,000,000)	(23,000,000)	(97,000,000)
Issues, Net-Liabilities																			(518,000,000)		(926,000,000)
Settlements, Net-Assets											(20,000,000)	(32,000,000)	(33,000,000)	(62,000,000)
Settlements, Net-Liabilities																			497,000,000	59,000,000	787,000,000	127,000,000
Transfers into Level 3							13,000,000	12,000,000	15,000,000	13,000,000	76,000,000	41,000,000	127,000,000	127,000,000	8,000,000		8,000,000
Transfers out of Level 3							(3,000,000)	(6,000,000)	(11,000,000)	(15,000,000)	(61,000,000)	(61,000,000)	(154,000,000)	(269,000,000)
Balance, at the end of the period		3,000,000	3,000,000	4,000,000	4,000,000	4,000,000	16,000,000	12,000,000	16,000,000	12,000,000	292,000,000	169,000,000	292,000,000	169,000,000	1,322,000,000	1,080,000,000	1,322,000,000	1,080,000,000
Balance, at the end of the period																			(4,677,000,000)	(4,726,000,000)	(4,677,000,000)	(4,726,000,000)
Changes in unrealized gains/ (losses) included in income relating to assets held							(1,000,000)		(1,000,000)			(1,000,000)	1,000,000	(1,000,000)	12,000,000	(27,000,000)	7,000,000	(61,000,000)	(34,000,000)	(15,000,000)
Changes in unrealized gains/ (losses) included in income relating to liabilities held																					(59,000,000)	(140,000,000)
Transfers between Level 1 and Level 2	$ 0