Segment Information (Operating Results) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	$ (1,621)	$ (4,465)	$ 1,165
Provision for income tax expense (benefit)	738	1,690	(247)
Net investment gains (losses)	(27)	(67)	5
Net derivative gains (losses)	(1,468)	(5,770)	(497)
Other Income	336	709	433
Net income (loss)	(883)	(2,775)	918
Annuities
Segment Reporting Information [Line Items]
Interest revenue	1,263	1,446	1,266
Interest expense	0	0	0
Life
Segment Reporting Information [Line Items]
Interest revenue	300	351	313
Interest expense	(4)	0	0
Run-off
Segment Reporting Information [Line Items]
Interest revenue	1,399	1,411	1,551
Interest expense	23	60	60
Corporate & Other
Segment Reporting Information [Line Items]
Interest revenue	142	197	97
Interest expense	39	67	69
Operating Segments
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	582	1,274	1,919
Provision for income tax expense (benefit)	459	341	512
Adjusted earnings	123	933	1,407
Operating Segments | Annuities
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	1,230	1,494	1,339
Provision for income tax expense (benefit)	323	441	329
Adjusted earnings	907	1,053	1,010
Operating Segments | Life
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(68)	6	(56)
Provision for income tax expense (benefit)	(30)	0	(21)
Adjusted earnings	(38)	6	(35)
Operating Segments | Run-off
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(466)	(249)	713
Provision for income tax expense (benefit)	(172)	(90)	247
Adjusted earnings	(294)	(159)	466
Operating Segments | Corporate & Other
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(114)	23	(77)
Provision for income tax expense (benefit)	338	(10)	(43)
Adjusted earnings	(452)	33	(34)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Provision for income tax expense (benefit)	1,197	2,031	265
Net investment gains (losses)	(27)	(67)	5
Net derivative gains (losses)	(1,468)	(5,770)	(497)
Other Income	$ (708)	$ 98	$ (262)