Consolidated Investment Entities (Details 2) (Consolidated Investment Entities, USD $)	3 Months Ended					3 Months Ended
	Mar. 31, 2013	Mar. 31, 2013 Corporate debt securities	Dec. 31, 2012 Corporate debt securities	Mar. 31, 2012 Corporate debt securities	Dec. 31, 2011 Corporate debt securities	Mar. 31, 2013 Common Stocks	Mar. 31, 2012 Common Stocks	Mar. 31, 2013 Syndicated loans	Mar. 31, 2012 Syndicated loans	Mar. 31, 2013 Other assets	Mar. 31, 2012 Other assets	Mar. 31, 2013 Debt	Mar. 31, 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	$ 14,000,000	$ 13,000,000	$ 202,000,000	$ 342,000,000	$ 1,214,000,000	$ 1,108,000,000
Balance, at the beginning of the period												(4,450,000,000)	(4,712,000,000)
Total Gains (Losses) Included in Net Income-Assets							(1,000,000)		3,000,000	(6,000,000)	(27,000,000)
Total Gains (Losses) Included in Net Income-Liabilities												(24,000,000)	(125,000,000)
Total Gains (Losses) Included in Other Comprehensive Income-Assets										(77,000,000)	32,000,000
Purchases, Net-Assets							6,000,000	76,000,000	7,000,000	51,000,000	12,000,000
Sales, Net-Assets							(2,000,000)	(18,000,000)	(5,000,000)	(6,000,000)	(90,000,000)
Issues, Net-Assets												(410,000,000)
Settlements, Net-Assets								(13,000,000)	(30,000,000)
Settlements, Net-Liabilities												289,000,000	68,000,000
Transfers into Level 3						2,000,000	1,000,000	51,000,000	86,000,000
Transfers out of Level 3						(8,000,000)	(9,000,000)	(93,000,000)	(208,000,000)
Balance, at the end of the period		3,000,000	3,000,000	4,000,000	4,000,000	8,000,000	8,000,000	205,000,000	195,000,000	1,176,000,000	1,035,000,000
Balance, at the end of the period												(4,595,000,000)	(4,769,000,000)
Changes in unrealized gains/ (losses) included in income relating to assets held										(5,000,000)	(34,000,000)
Changes in unrealized gains/ (losses) included in income relating to liabilities held									2,000,000			(24,000,000)	(125,000,000)
Transfers between Level 1 and Level 2	$ 0