Fair Value Measurements (Details 2) (USD $) In Millions, unless otherwise specified							12 Months Ended
	Dec. 31, 2011 Equity Securities [Member] Available-for-sale Securities [Member]	Dec. 31, 2010 Equity Securities [Member] Available-for-sale Securities [Member]	Dec. 31, 2009 Equity Securities [Member] Available-for-sale Securities [Member]	Dec. 31, 2011 Fixed Maturities, FVO [Member]	Dec. 31, 2010 Fixed Maturities, FVO [Member]	Dec. 31, 2009 Fixed Maturities, FVO [Member]	Dec. 31, 2011 Freestanding Derivatives [Member]	Dec. 31, 2010 Freestanding Derivatives [Member]	Dec. 31, 2011 Freestanding Derivatives [Member] Hedging Derivatives [Member] International [Member]	Dec. 31, 2010 Freestanding Derivatives [Member] Hedging Derivatives [Member] International [Member]	Dec. 31, 2011 Freestanding Derivatives [Member] Hedging Derivatives [Member] Guaranteed Minimum Withdrawal Benefit [Member] U.S. [Member]	Dec. 31, 2010 Freestanding Derivatives [Member] Hedging Derivatives [Member] Guaranteed Minimum Withdrawal Benefit [Member] U.S. [Member]	Dec. 31, 2011 Freestanding Derivatives [Member] US Macro Hedge Program [Member]	Dec. 31, 2010 Freestanding Derivatives [Member] US Macro Hedge Program [Member]	Dec. 31, 2011 Freestanding Derivatives [Member] Credit derivative [Member]	Dec. 31, 2010 Freestanding Derivatives [Member] Credit derivative [Member]	Dec. 31, 2011 Freestanding Derivatives [Member] Equity derivative [Member]	Dec. 31, 2010 Freestanding Derivatives [Member] Equity derivative [Member]	Dec. 31, 2011 Freestanding Derivatives [Member] Interest rate derivatives [Member]	Dec. 31, 2010 Freestanding Derivatives [Member] Interest rate derivatives [Member]	Dec. 31, 2011 Freestanding Derivatives [Member] Other Derivatives Contracts [Member]	Dec. 31, 2010 Freestanding Derivatives [Member] Other Derivatives Contracts [Member]
Roll Forward of Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair Value of Financial Instruments (Assets), Measured at Fair Value on a Recurring Basis, Beginning Balance	$ 93	$ 154	$ 58	$ 495	$ 522	$ 0
Fair Value of Financial Instruments (Assets Netted Against Liabilities), Measured at Fair Value on a Recurring Basis, Beginning Balance							401	337	5	12	600	236	203	278	(390)	(228)	4	(2)	(53)	5	32	36
Total realized/unrealized gains (losses) on Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value, Included in Net Income							(56)	(293)	(3)	(29)	279	(74)	(128)	(312)	(170)	124	(9)	6	(21)	(4)	(4)	(4)
Total realized/unrealized gains (losses) on Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value, Included in OCI								1												1
Purchases of Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value							513		33		23		347		1		45		64
Settlements of Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value							(134)				(19)		(65)		(2)				(48)
Purchases, issuances and settlements of Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value								661		22		442		237		4				(44)
Transfers into Level 3 of Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value								(290)								(290)
Transfers out of Level 3 of Financial Instruments (Assets Netted Against Liabilities) Measured at Fair Value								(15)				(4)								(11)
Fair Value of Financial Instruments (Assets Netted Against Liabilities), Measured at Fair Value on a Recurring Basis, Ending Balance							724	401	35	5	883	600	357	203	(561)	(390)	40	4	(58)	(53)	28	32
Fair Value of Financial Instruments (Assets), Measured at Fair Value on a Recurring Basis, Ending Balance	93	154	58	495	522	0
Changes in unrealized gains (losses) included in net income related to Financial Instruments (Assets Netted Against Liabilities) still held at a reporting date							$ (28)	$ (288)	$ (5)	$ (29)	$ 278	$ (61)	$ (107)	$ (292)	$ (163)	$ 116	$ (8)	$ 6	$ (19)	$ (24)	$ (4)	$ (4)