Equity (Reclassifications Out of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	$ 257	$ 382	$ 538	$ 535
Net derivative gains (losses)	(1,051)	485	(1,815)	394
Net investment income	5,464	3,959	14,910	14,367
Other expenses	(3,928)	(4,533)	(11,366)	(12,665)
Income (loss) from continuing operations before provision for income tax	548	2,163	3,370	6,335
Provision for income tax expense (benefit)	25	(965)	(480)	(1,855)
Net income (loss)	573	1,198	2,890	4,480
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)	141	(131)	246	(166)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Investment Gains (Losses), Net of Related Offsets
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net investment gains (losses)	163	104	288	353
Net derivative gains (losses)	6	(5)	28	(21)
Net investment income	4	3	23	60
Income (loss) from continuing operations before provision for income tax	173	102	339	392
Provision for income tax expense (benefit)	(60)	(34)	(114)	(134)
Net income (loss)	113	68	225	258
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from continuing operations before provision for income tax	94	(239)	174	(490)
Provision for income tax expense (benefit)	(30)	77	(55)	178
Net income (loss)	64	(162)	119	(312)
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Interest rate swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net derivative gains (losses)	28	40	56	52
Net investment income	4	3	11	9
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Interest rate forwards
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net derivative gains (losses)	1	1	2	5
Net investment income	1	1	4	3
Other expenses	0	1	1	2
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Foreign currency swaps
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net derivative gains (losses)	59	(286)	96	(563)
Net investment income	0	0	(1)	(1)
Other expenses	0	0	1	1
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gains (Losses) on Derivatives | Credit forwards
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net derivative gains (losses)	0	1	3	1
Net investment income	1	0	1	1
Reclassification out of Accumulated Other Comprehensive Income | Defined Benefit Plans Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of net actuarial gains (losses)	(47)	(58)	(150)	(174)
Amortization of prior service (costs) credit	1	1	5	3
Income (loss) from continuing operations before provision for income tax	(46)	(57)	(145)	(171)
Provision for income tax expense (benefit)	10	20	47	59
Net income (loss)	$ (36)	$ (37)	$ (98)	$ (112)