Fair Value Measurement (Details 3) (USD $) In Millions, unless otherwise specified			3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended		3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended
	Jun. 30, 2013 Other invested assets	Dec. 31, 2012 Other invested assets	Sep. 30, 2013 Level 3 Obligations of state and political subdivisions		Sep. 30, 2012 Level 3 Obligations of state and political subdivisions		Sep. 30, 2013 Level 3 Obligations of state and political subdivisions		Sep. 30, 2012 Level 3 Obligations of state and political subdivisions		Sep. 30, 2013 Level 3 RMBS		Sep. 30, 2012 Level 3 RMBS		Sep. 30, 2013 Level 3 RMBS		Sep. 30, 2012 Level 3 RMBS		Sep. 30, 2013 Level 3 Asset-backed securities		Sep. 30, 2012 Level 3 Asset-backed securities		Sep. 30, 2013 Level 3 Asset-backed securities		Sep. 30, 2012 Level 3 Asset-backed securities		Sep. 30, 2013 Level 3 Corporate securities		Sep. 30, 2013 Level 3 Corporate securities		Sep. 30, 2013 Level 3 Other invested assets		Sep. 30, 2012 Level 3 Other invested assets		Sep. 30, 2013 Level 3 Other invested assets		Sep. 30, 2012 Level 3 Other invested assets		Sep. 30, 2013 Level 3 FG VIEs' assets, at fair value		Sep. 30, 2012 Level 3 FG VIEs' assets, at fair value		Sep. 30, 2013 Level 3 FG VIEs' assets, at fair value		Sep. 30, 2012 Level 3 FG VIEs' assets, at fair value		Sep. 30, 2013 Level 3 Other assets		Sep. 30, 2012 Level 3 Other assets		Sep. 30, 2013 Level 3 Other assets		Sep. 30, 2012 Level 3 Other assets		Sep. 30, 2013 Level 3 Credit Derivative, Asset, Liability Net		Sep. 30, 2012 Level 3 Credit Derivative, Asset, Liability Net		Sep. 30, 2013 Level 3 Credit Derivative, Asset, Liability Net		Sep. 30, 2012 Level 3 Credit Derivative, Asset, Liability Net		Sep. 30, 2013 Level 3 FG VIEs' liabilities with recourse, at fair value		Sep. 30, 2012 Level 3 FG VIEs' liabilities with recourse, at fair value		Sep. 30, 2013 Level 3 FG VIEs' liabilities with recourse, at fair value		Sep. 30, 2012 Level 3 FG VIEs' liabilities with recourse, at fair value		Sep. 30, 2013 Level 3 FG VIEs' liabilities without recourse, at fair value		Sep. 30, 2012 Level 3 FG VIEs' liabilities without recourse, at fair value		Sep. 30, 2013 Level 3 FG VIEs' liabilities without recourse, at fair value		Sep. 30, 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	$ 2	$ 1	$ 36		$ 10		$ 35		$ 10		$ 276		$ 167		$ 219		$ 134		$ 300		$ 274		$ 306		$ 235		$ 0		$ 0				$ 1				$ 2		$ 2,674		$ 2,726		$ 2,688		$ 2,819		$ 23		$ 44		$ 36		$ 54		$ (2,248)	[1]	$ (1,666)		$ (1,793)	[1]	$ (1,304)		$ (1,940)		$ (2,239)		$ (2,090)		$ (2,397)		$ (1,134)		$ (1,042)		$ (1,051)		$ (1,061)
Net Income (loss)			0	[2],[3]	0	[2],[3]	1	[2],[3]	0	[2],[3]	4	[2],[3]	4	[2],[3]	15	[2],[3]	9	[2],[3]	6	[2],[3]	6	[2]	15	[2],[3]	20	[2]	1	[2],[3]	1	[2],[3]	0	[2],[4]	0	[2],[5]	(1)	[2],[4]	0	[2],[5]	(30)	[2],[5]	91	[2],[6]	526	[2],[5]	266	[2],[6]	9	[2],[6]	(2)	[1],[2],[7]	(4)	[2],[6]	(12)	[1],[2],[7]	354	[1],[2],[7]	(36)	[2],[5]	(164)	[1],[2],[7]	(466)	[2],[5]	28	[2],[5]	(51)	[2],[5]	(135)	[2],[5]	(150)	[2],[5]	35	[2],[5]	(19)		(157)	[2],[5]	(112)
Other comprehensive income (loss)			6	[2]	0	[2]	7	[2]	1	[2]	12	[2]	13	[2]	16	[2]	6	[2]	(2)	[2]	20	[2]	(24)	[2]	8	[2]	4	[2]	4	[2]	0	[2]	0	[2]	2	[2]	(1)	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[1],[2]	0	[2]	0	[1],[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]
Purchases			0		1	[2]	0		1	[2]	9		42	[2]	79		97	[2]	38		1	[2]	49		41	[2]	130	[8]	130		0		0	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0	[1]	0	[2]	0	[1]	0	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0		0	[2]
Settlements			(1)		0	[2]	(2)		(1)	[2]	(14)		(17)	[2]	(42)		(37)	[2]	(2)		(2)	[2]	(6)		(5)	[2]	(3)		(3)		(2)		0	[2]	(2)		0	[2]	(113)		(124)	[2]	(553)		(407)	[2]	0		0	[2]	0		0	[2]	(27)	[1]	1	[2]	36	[1]	69	[2]	84		121	[2]	274		398	[2]	36		43	[2]	135		155	[2]
FG VIE Consolidations			0		0	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0		0	[2]	0		0										0		0	[2]	48		15	[2]																	0		0	[2]	(12)		(20)	[2]	0		0	[2]	(37)		0	[2]
FG VIE deconsolidations																																							(16)				(194)																				0				135				16				63
Balance at the end of the period	2	1	41		11		41		11		287		209		287		209		340		299		340		299		132		132		0		1		0		1		2,515		2,693		2,515		2,693		32		42		32		42		(1,921)	[1]	(1,701)	[1]	(1,921)	[1]	(1,701)	[1]	(1,828)		(2,169)		(1,828)		(2,169)		(1,047)		(1,018)		(1,047)		(1,018)
Total pre-tax realized/unrealized gains/(losses) recorded in
Change in unrealized gains/(losses) related to financial instruments held at the reporting date			$ 5		$ 0		$ 7		$ 1		$ 12		$ 10		$ 16		$ 2		$ (2)		$ 20		$ (23)		$ 8		$ 4		$ 4		$ 0		$ 0		$ 2		$ (1)		$ 20		$ 165		$ 450		$ 468		$ 9		$ (2)	[1]	$ (4)		$ (12)	[1]	$ 331	[1]	$ (39)		$ 14	[1]	$ (391)		$ 24		$ (55)		$ (141)		$ (180)		$ (20)		$ (58)		$ (246)		$ (213)

[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] Reported in other income.

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

[6] Recorded in fair value gains (losses) on CCS.

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

[8] Non-cash transaction.