Fair Value Measurements (Details 5) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011		Mar. 31, 2012	Mar. 31, 2011
Reinsurance Recoverable [Member] | Guaranteed Withdrawal Benefits [Member] | U.S. [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					$ 443		$ 280		$ 376	$ 237
Total realized/unrealized gains (losses) included in net income	(184)	[1],[2],[3]	241	[1],[2],[3]	(265)	[1],[2],[3]	180	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI		[4]		[4]		[4]		[4]
Purchases
Settlements	7		7		21		25
Sales
Transfers into Level 3		[5]		[5]		[5]		[5]
Transfers out of Level 3		[5]		[5]		[5]		[5]
Fair value, Ending Balance	199		485		199		485		376	237
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	(184)	[1],[6]	241	[1],[6]	(265)	[1],[6]	180	[1],[6]
Separate Accounts [Member]
Roll Forward of Financial Instruments (Assets) Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)
Fair value, Beginning Balance					1,031		1,247		1,335	1,068
Total realized/unrealized gains (losses) included in net income	(2)	[1],[2],[3]	11	[1],[2],[3]	31	[1],[2],[3]	35	[1],[2],[3]
Total realized/unrealized gains (losses) included in OCI		[4]		[4]		[4]		[4]
Purchases	97		131		336		165
Settlements					(1)
Sales	(41)		(11)		(442)		(180)
Transfers into Level 3	(3)	[5]	1	[5]	451	[5]	13	[5]
Transfers out of Level 3	(7)	[5]	(16)	[5]	(27)	[5]	(96)	[5]
Fair value, Ending Balance	1,379		1,184		1,379		1,184		1,335	1,068
Changes in unrealized gains (losses) included in net income related to financial instruments still held at end of period	$ 8	[1],[6]	$ 8	[1],[6]	$ (18)	[1],[6]	$ 9	[1],[6]

[1] All amounts in these rows are reported in net realized capital gains/losses. The realized/unrealized gains (losses) included in net income for separate account assets are offset by an equal amount for separate account liabilities, which results in a net zero impact on net income for the Company. All amounts are before income taxes and amortization DAC.

[2] Includes both market and non-market impacts in deriving realized and unrealized gains (losses).

[3] The Company classifies gains and losses on GMWB reinsurance derivatives and Guaranteed Living Benefit embedded derivatives as unrealized gains (losses) for purposes of disclosure in this table because it is impracticable to track on a contract-by-contract basis the realized gains (losses) for these derivatives and embedded derivatives.

[4] All amounts are before income taxes and amortization of DAC.

[5] Transfers in and/or (out) of Level 3 are primarily attributable to the availability of market observable information and the re-evaluation of the observability of pricing inputs.

[6] Amounts presented are for Level 3 only and therefore may not agree to other disclosures included herein.