Guaranteed Benefit Features - Separate Account Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Separate account liability	$ 77,605	$ 66,185
Additional liability balance:
Additional liability for FIA guaranteed withdrawal benefits	14,000	13,600
Fixed-indexed annuities
Additional liability balance:
Additional liability for FIA guaranteed withdrawal benefits	157	147
Variable Life and Universal Life
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Separate account liability	519	488
Additional liability balance:
Beginning balance	1,315	1,197	$ 1,095
Incurred guaranteed benefits	101	614	554
Paid guaranteed benefits	(235)	(496)	(452)
Ending balance	1,181	1,315	1,197
Reinsurance on additional liability balance	1,304	1,006	935	$ 874
Stabilizer and MCGs
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Separate account liability	37,219	37,577
Additional liability balance:
Beginning balance	150	161	103
Incurred guaranteed benefits	(53)	(11)	58
Paid guaranteed benefits	0	0	0
Ending balance	97	150	161
Stabilizer and MCGs | Separate Account Liability
Additional liability balance:
Externally managed assets included in Separate account liability not reported on balance sheet	30,000	30,000
Other Retained Business
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Separate account liability	2,308	2,291
Additional liability balance:
Beginning balance	73	70	54
Incurred guaranteed benefits	(28)	5	19
Paid guaranteed benefits	(1)	(2)	(3)
Ending balance	44	73	70
Held for sale | GMDB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Separate account liability	28,701	30,839
Additional liability balance:
Beginning balance	508	516	374
Incurred guaranteed benefits	(15)	128	231
Paid guaranteed benefits	(107)	(136)	(89)
Ending balance	386	508	516
Reinsurance on additional liability balance	22	29	33	$ 31
Held for sale | GMWBL/GMWB/GMAB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Separate account liability	14,112	13,845
Additional liability balance:
Beginning balance	1,512	1,849	1,508
Incurred guaranteed benefits	(354)	(336)	342
Paid guaranteed benefits	0	(1)	(1)
Ending balance	1,158	1,512	1,849
Held for sale | GMIB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Separate account liability	7,247	9,806
Additional liability balance:
Beginning balance	1,345	1,414	1,136
Incurred guaranteed benefits	(629)	449	440
Paid guaranteed benefits	(83)	(518)	(162)
Ending balance	$ 633	$ 1,345	$ 1,414