Segment Information (Operating Results) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	$ (24)	$ (610)
Provision for income tax expense (benefit)	(22)	(245)
Net investment gains (losses)	(4)	(55)
Net derivative gains (losses)	(287)	(813)
Other adjustments to net income	79	62
Net income (loss)	(2)	(365)
Annuities
Segment Reporting Information [Line Items]
Interest revenue	359	324
Interest expense	0	0
Life
Segment Reporting Information [Line Items]
Interest revenue	88	80
Interest expense	0	0
Run-off
Segment Reporting Information [Line Items]
Interest revenue	343	374
Interest expense	0	15
Corporate & Other
Segment Reporting Information [Line Items]
Interest revenue	10	56
Interest expense	1	18
Operating Segments
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	366	279
Provision for income tax expense (benefit)	60	64
Adjusted earnings	306	215
Operating Segments | Annuities
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	255	265
Provision for income tax expense (benefit)	44	67
Adjusted earnings	211	198
Operating Segments | Life
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	64	(126)
Provision for income tax expense (benefit)	12	(32)
Adjusted earnings	52	(94)
Operating Segments | Run-off
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	64	113
Provision for income tax expense (benefit)	13	25
Adjusted earnings	51	88
Operating Segments | Corporate & Other
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(17)	27
Provision for income tax expense (benefit)	(9)	4
Adjusted earnings	(8)	23
Segment Reconciling Items
Segment Reporting Information [Line Items]
Provision for income tax expense (benefit)	82	309
Net investment gains (losses)	(4)	(55)
Net derivative gains (losses)	(287)	(813)
Other adjustments to net income	$ (99)	$ (21)