Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pre-tax
Unrealized net holding gains arising during the period, net of related offsets, Pre-tax	$ 1,177	$ (103)	$ 2,337	$ 869
Less: reclassification adjustment of realized capital gains and losses, Pre-tax	(70)	527	63	688
Unrealized net capital gains and losses, Pre-tax	1,247	(630)	2,274	181
Unrealized foreign currency translation adjustments, Pre-tax	19	(51)	22	(29)
Unrecognized pension and other postretirement benefit cost, Pre-tax	30	32	96	79
Other comprehensive income (loss), Pre-tax	1,296	(649)	2,392	231
Tax
Unrealized net holding gains arising during the period, net of related offsets, Tax	(412)	36	(816)	(305)
Less: reclassification adjustment of realized capital gains and losses, Tax	25	(184)	(22)	(241)
Unrealized net capital gains and losses, Tax	(437)	220	(794)	(64)
Unrealized foreign currency translation adjustments, Tax	(7)	18	(8)	10
Unrecognized pension and other postretirement benefit cost, Tax	(10)	(11)	(32)	(26)
Other comprehensive income (loss), Tax	(454)	227	(834)	(80)
After-tax
Unrealized net holding gains arising during the period, net of related offsets, After-tax	765	(67)	1,521	564
Less: reclassification adjustment of realized capital gains and losses, After-tax	(45)	343	41	447
Unrealized net capital gains and losses, After-tax	810	(410)	1,480	117
Unrealized foreign currency translation adjustments, After-tax	12	(33)	14	(19)
Unrecognized pension and other postretirement benefit cost, After-tax	20	21	64	53
Other comprehensive income (loss), after-tax	842	(422)	1,558	151
Net income	723	175	1,912	75
Comprehensive income (loss)	$ 1,565	$ (247)	$ 3,470	$ 226