Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pre-tax
Unrealized net holding gains and losses arising during the period, net of related offsets, Pre-tax	$ (203)	$ 68	$ 777	$ (1,285)
Less: reclassification adjustment of realized capital gains and losses, Pre-tax	293	(28)	499	438
Unrealized net capital gains and losses, Pre-tax	(496)	96	278	(1,723)
Unrecognized pension and other postretirement benefit cost arising during the period, Pre-tax	4	934	4	943
Less: reclassification adjustment of net periodic cost recognized in operating costs and expenses, Pre-tax	(14)	(117)	(42)	(247)
Unrecognized pension and other postretirement benefit cost, Pre-tax	18	1,051	46	1,190
Unrealized foreign currency translation adjustments, Pre-tax	(26)	20	(31)	(31)
Other comprehensive (loss) income	(504)	1,167	293	(564)
Tax
Unrealized net holding gains and losses arising during the period, net of related offsets, Tax	70	(23)	(272)	450
Less: reclassification adjustment of realized capital gains and losses, Tax	(103)	10	(175)	(153)
Unrealized net capital gains and losses, Tax	173	(33)	(97)	603
Unrecognized pension and other postretirement benefit cost arising during the period, Tax	(2)	(327)	(1)	(329)
Less: reclassification adjustment of net periodic cost recognized in operating costs and expenses, Tax	4	40	14	86
Unrecognized pension and other postretirement benefit cost, Tax	(6)	(367)	(15)	(415)
Unrealized foreign currency translation adjustments, Tax	9	(7)	11	11
Other comprehensive income (loss), Tax	176	(407)	(101)	199
After-tax
Unrealized net holding gains and losses arising during the period, net of related offsets, After-tax	(133)	45	505	(835)
Less: reclassification adjustment of realized capital gains and losses, After-tax	190	(18)	324	285
Unrealized net capital gains and losses, After-tax	(323)	63	181	(1,120)
Unrecognized pension and other postretirement benefit cost arising during the period, After-tax	2	607	3	614
Less: reclassification adjustment of net periodic cost recognized in operating costs and expenses, After-tax	(10)	(77)	(28)	(161)
Unrecognized pension and other postretirement benefit cost, After-tax	12	684	31	775
Unrealized foreign currency translation adjustments, After-tax	(17)	13	(20)	(20)
Other comprehensive (loss) income, after-tax	(328)	760	192	(365)
Net income	781	316	2,026	1,459
Comprehensive income	$ 453	$ 1,076	$ 2,218	$ 1,094