Fair Value Measurement (Details 3) (USD $) In Millions, unless otherwise specified		3 Months Ended
	Dec. 31, 2012 Other invested assets	Mar. 31, 2013 Level 3 Obligations of state and political subdivisions		Mar. 31, 2012 Level 3 Obligations of state and political subdivisions		Mar. 31, 2013 Level 3 RMBS		Mar. 31, 2012 Level 3 RMBS		Mar. 31, 2013 Level 3 Asset-backed securities		Mar. 31, 2012 Level 3 Asset-backed securities		Mar. 31, 2013 Level 3 Other invested assets		Mar. 31, 2012 Level 3 Other invested assets		Mar. 31, 2013 Level 3 FG VIEs' assets, at fair value		Mar. 31, 2012 Level 3 FG VIEs' assets, at fair value		Mar. 31, 2013 Level 3 Other assets		Mar. 31, 2012 Level 3 Other assets		Mar. 31, 2013 Level 3 Credit Derivative, Asset, Liability Net		Mar. 31, 2012 Level 3 Credit Derivative, Asset, Liability Net		Mar. 31, 2013 Level 3 FG VIEs' liabilities with recourse, at fair value		Mar. 31, 2012 Level 3 FG VIEs' liabilities with recourse, at fair value		Mar. 31, 2013 Level 3 FG VIEs' liabilities without recourse, at fair value		Mar. 31, 2012 Level 3 FG VIEs' liabilities without recourse, at fair value
Total pretax realized and unrealized gains/(losses) recorded in
Balance at the beginning of the period	$ 1	$ 35		$ 10		$ 219		$ 134		$ 306		$ 235				$ 2		$ 2,688		$ 2,819		$ 36		$ 54		$ (1,793)	[1]	$ (1,304)		$ (2,090)		$ (2,397)		$ (1,051)		$ (1,061)
Net Income (loss)		1	[2],[3]	0	[2],[3]	5	[2],[3]	1	[2],[3]	4	[2],[3]	6	[2]	0	[2]	0	[2],[4]	215	[2],[4]	132	[2],[5]	(10)	[2],[5]	(14)	[1],[2],[6]	(592)	[1],[2],[6]	(691)	[2],[4]	(81)	[2],[4]	(86)	[2],[4]	(74)	[2],[4]	(80)
Other comprehensive income (loss)		0	[2]	0	[2]	7	[2]	10	[2]	(22)	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[1],[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]
Purchases		0		0	[2]	3		0	[2]	0		18	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0	[1]	0	[2]	0		0	[2]	0		0	[2]
Settlements		(1)		(1)	[2]	(11)		(9)	[2]	(2)		(1)	[2]	0		0	[2]	(138)		(138)	[2]	0		0	[2]	(8)	[1]	42	[2]	112		138	[2]	55		55	[2]
FG VIE Consolidations		0		0	[2]	(2)		0	[2]	0		0	[2]					48		15	[2]									(12)		(20)	[2]	(37)			[2]
Balance at the end of the period	1	35		9		221		136		286		258		1		2		2,813		2,828		26		40		(2,393)	[1]	(1,953)	[1]	(2,071)		(2,365)		(1,107)		(1,086)
Total pre-tax realized/unrealized gains/(losses) recorded in
Change in unrealized gains/(losses) related to financial instruments held at the reporting date		$ 0		$ 0		$ 9		$ 10		$ (22)		$ 0		$ 0		$ 0		$ 199		$ 231		$ (10)		$ (14)	[1]	$ (611)	[1]	$ (635)		$ (83)		$ (107)		$ (94)		$ (118)

[1] Represents net position of credit derivatives. The consolidated balance sheet presents gross assets and liabilities based on net counterparty exposure.

[2] Realized and unrealized gains (losses) from changes in values of Level 3 financial instruments represent gains (losses) from changes in values of those financial instruments only for the periods in which the instruments were classified as Level 3.

[3] Included in net realized investment gains (losses) and net investment income.

[4] Included in fair value gains (losses) on FG VIEs.

[5] Recorded in fair value gains (losses) on committed capital securities.

[6] Reported in net change in fair value of credit derivatives.