Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pre-tax
Unrealized net holding gains and losses arising during the period, net of related offsets, Pre-tax	$ (1,278)	$ 2,428	$ 1,493
Less: reclassification adjustment of realized capital gains and losses, Pre-tax	549	225	795
Unrealized net capital gains and losses, Pre-tax	(1,827)	2,203	698
Unrecognized pension and other postretirement benefit cost arising during the period, Pre-tax	1,231	(634)	(517)
Less: reclassification adjustment of net periodic cost recognized in operating costs and expenses, Pre-tax	(445)	(166)	(146)
Unrecognized pension and other postretirement benefit cost, Pre-tax	1,676	(468)	(371)
Unrealized foreign currency translation adjustments, Pre-tax	(49)	22	(18)
Other comprehensive (loss) income, Pre-tax	(200)	1,757	309
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets, Tax	447	(848)	(524)
Less: reclassification adjustment of realized capital gains and losses, Tax	(192)	(79)	(278)
Unrealized net capital gains and losses, Tax	639	(769)	(246)
Unrecognized pension and other postretirement benefit cost arising during the period, Tax	(429)	224	183
Less: reclassification adjustment of net periodic cost recognized in operating costs and expenses, Tax	156	58	51
Unrecognized pension and other postretirement benefit cost, Tax	(585)	166	132
Unrealized foreign currency translation adjustments, Tax	17	(8)	6
Other comprehensive (loss) income, Tax	71	(611)	(108)
After-tax
Unrealized net holding gains and losses arising during the period, net of related offsets, After-tax	(831)	1,580	969
Less: reclassification adjustment of realized capital gains and losses, After-tax	357	146	517
Unrealized net capital gains and losses, After-tax	(1,188)	1,434	452
Unrecognized pension and other postretirement benefit cost arising during the period, After-tax	802	(410)	(334)
Less: reclassification adjustment of net periodic cost recognized in operating costs and expenses, After-tax	(289)	(108)	(95)
Unrecognized pension and other postretirement benefit cost, After-tax	1,091	(302)	(239)
Unrealized foreign currency translation adjustments, After-tax	(32)	14	(12)
Other comprehensive (loss) income, after-tax	$ (129)	$ 1,146	$ 201