Fair Value of Assets and Liabilities - Rollforward of level 3 assets and liabilities held at fair value on a recurring basis during the period (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	$ 610	$ 777	$ 697	$ 837
Total gains (losses) included in: net income	12	9	48	24
Total gains (losses) included in: OCI	1	(2)	7	(5)
Transfers into Level 3	50	44	70	78
Transfers out of Level 3	(42)	(62)	(204)	(203)
Purchases	143	90	331	295
Sales	(3)	(29)	(168)	(161)
Issues	0	0	0	0
Settlements	(4)	(31)	(14)	(69)
Balance at end of period	767	796	767	796
Fair Value Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation
Balance at the beginning of the period	(437)	(260)	(224)	(286)
Total gains (losses) included in: net income	(14)	(7)	(54)	17
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	(175)	0
Transfers out of Level 3	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	(9)	0	(9)	(1)
Settlements	6	1	8	4
Balance at the end of the period	(454)	(266)	(454)	(266)
Total	(2)	2	(6)	41
Realized capital gains and losses
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	7	9	38	24
Net investment income
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	5	0	10	0
Interest credited to contractholder funds
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	(13)	(9)	(56)	10
Life contract benefits
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	(1)	2	2	7
Municipal
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	63	106	70	101
Total gains (losses) included in: net income	0	0	0	1
Total gains (losses) included in: OCI	2	(1)	4	(2)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(9)	(5)	(11)
Purchases	0	0	0	10
Sales	(1)	(6)	(4)	(8)
Issues	0	0	0	0
Settlements	0	(1)	(1)	(2)
Balance at end of period	64	89	64	89
Corporate - public
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	46	76	70	108
Total gains (losses) included in: net income	0	0	0	0
Total gains (losses) included in: OCI	1	(1)	3	(3)
Transfers into Level 3	0	12	0	16
Transfers out of Level 3	(7)	(4)	(47)	(9)
Purchases	66	10	86	10
Sales	(2)	(1)	(7)	(27)
Issues	0	0	0	0
Settlements	0	0	(1)	(3)
Balance at end of period	104	92	104	92
Corporate - privately placed
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	89	195	90	224
Total gains (losses) included in: net income	0	1	(1)	(1)
Total gains (losses) included in: OCI	(1)	(1)	1	(2)
Transfers into Level 3	0	0	15	20
Transfers out of Level 3	0	(20)	(2)	(49)
Purchases	1	6	2	21
Sales	0	(2)	(13)	(5)
Issues	0	0	0	0
Settlements	(2)	(12)	(5)	(41)
Balance at end of period	87	167	87	167
ABS - CDO
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	10	9	6	99
Total gains (losses) included in: net income	1	0	1	0
Total gains (losses) included in: OCI	0	1	0	1
Transfers into Level 3	50	20	51	20
Transfers out of Level 3	(5)	0	(5)	(89)
Purchases	8	0	11	0
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	(1)	(1)	(1)	(2)
Balance at end of period	63	29	63	29
ABS - consumer and other
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	43	73	63	48
Total gains (losses) included in: net income	0	0	0	0
Total gains (losses) included in: OCI	0	0	0	1
Transfers into Level 3	0	12	0	22
Transfers out of Level 3	(30)	(29)	(145)	(45)
Purchases	3	33	124	108
Sales	0	(20)	(22)	(62)
Issues	0	0	0	0
Settlements	(1)	(17)	(5)	(20)
Balance at end of period	15	52	15	52
Residential mortgage-backed securities (“RMBS”)
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	1		0
Total gains (losses) included in: net income	0		0
Total gains (losses) included in: OCI	(1)		(1)
Transfers into Level 3	0		1
Transfers out of Level 3	0		0
Purchases	0		0
Sales	0		0
Issues	0		0
Settlements	0		0
Balance at end of period	0		0
Commercial mortgage-backed securities (“CMBS”)
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	34	26	26	26
Total gains (losses) included in: net income	0	0	0	0
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	3	0
Transfers out of Level 3	0	0	0	0
Purchases	0	0	6	1
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	0	0	(1)	(1)
Balance at end of period	34	26	34	26
Fixed income securities
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	286	485	325	606
Total gains (losses) included in: net income	1	1	0	0
Total gains (losses) included in: OCI	1	(2)	7	(5)
Transfers into Level 3	50	44	70	78
Transfers out of Level 3	(42)	(62)	(204)	(203)
Purchases	78	49	229	150
Sales	(3)	(29)	(46)	(102)
Issues	0	0	0	0
Settlements	(4)	(31)	(14)	(69)
Balance at end of period	367	455	367	455
Equity securities
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	319	291	341	210
Total gains (losses) included in: net income	11	8	49	24
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Purchases	55	21	77	100
Sales	0	0	(82)	(14)
Issues	0	0	0	0
Settlements	0	0	0	0
Balance at end of period	385	320	385	320
Short-term investments
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	5	0	30	20
Total gains (losses) included in: net income	0	0	0	0
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Purchases	10	20	25	45
Sales	0	0	(40)	(45)
Issues	0	0	0	0
Settlements	0	0	0	0
Balance at end of period	15	20	15	20
Free-standing derivatives, net
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	0	1	1	1
Total gains (losses) included in: net income	0	0	(1)	0
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	0	0	0	0
Settlements	0	0	0	0
Balance at end of period	0	1	0	1
Contractholder funds: Derivatives embedded in life and annuity contracts
Fair Value Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation
Balance at the beginning of the period	(437)	(260)	(224)	(286)
Total gains (losses) included in: net income	(14)	(7)	(54)	17
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	(175)	0
Transfers out of Level 3	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	(9)	0	(9)	(1)
Settlements	6	1	8	4
Balance at the end of the period	$ (454)	$ (266)	$ (454)	$ (266)