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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	$ 774	$ 610	$ 738	$ 697
Total gains (losses) included in: net income	2	12	(14)	48
Total gains (losses) included in: OCI	10	1	(5)	7
Transfers into Level 3	20	50	83	70
Transfers out of Level 3	(75)	(42)	(116)	(204)
Purchases	186	143	267	331
Sales	(47)	(3)	(52)	(168)
Issues	0	0	0	0
Settlements	(15)	(4)	(46)	(14)
Balance at end of period	855	767	855	767
Fair Value Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation
Balance at the beginning of the period	(488)	(437)	(462)	(224)
Total gains (losses) included in: net income	(6)	(14)	(27)	(54)
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	0	(175)
Transfers out of Level 3	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	(10)	(9)	(25)	(9)
Settlements	7	6	17	8
Balance at the end of the period	(497)	(454)	(497)	(454)
Total	(4)	(2)	(41)	(6)
Net investment income
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	(2)	5	(24)	10
Realized capital gains and losses
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	4	7	10	38
Interest credited to contractholder funds
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	8	(1)	(6)	2
Interest credited to contractholder funds
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Total gains (losses) included in: net income	(14)	(13)	(21)	(56)
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	(488)	(437)	(462)	(224)
Total gains (losses) included in: net income	(6)	(14)	(27)	(54)
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	0	(175)
Transfers out of Level 3	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issues	(10)	(9)	(25)	(9)
Settlements	7	6	17	8
Balance at the end of the period	(497)	(454)	(497)	(454)
Municipal
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	83	63	62	70
Total gains (losses) included in: net income	0	0	1	0
Total gains (losses) included in: OCI	0	2	2	4
Transfers into Level 3	20	0	20	0
Transfers out of Level 3	(32)	0	(10)	(5)
Purchases	0	0	0	0
Sales	(2)	(1)	(4)	(4)
Issues	0	0	0	0
Settlements	0	0	(2)	(1)
Balance at end of period	69	64	69	64
Corporate - public
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	67	46	61	70
Total gains (losses) included in: net income	0	0	(2)	0
Total gains (losses) included in: OCI	9	1	1	3
Transfers into Level 3	0	0	1	0
Transfers out of Level 3	0	(7)	0	(47)
Purchases	70	66	76	86
Sales	(10)	(2)	0	(7)
Issues	0	0	0	0
Settlements	0	0	(1)	(1)
Balance at end of period	136	104	136	104
Corporate - privately placed
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	126	89	114	90
Total gains (losses) included in: net income	0	0	2	(1)
Total gains (losses) included in: OCI	0	(1)	(6)	1
Transfers into Level 3	0	0	11	15
Transfers out of Level 3	(39)	0	(32)	(2)
Purchases	35	1	37	2
Sales	(2)	0	(6)	(13)
Issues	0	0	0	0
Settlements	(1)	(2)	(1)	(5)
Balance at end of period	119	87	119	87
ABS
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	50	53	65	69
Total gains (losses) included in: net income	0	1	(1)	1
Total gains (losses) included in: OCI	1	0	(1)	0
Transfers into Level 3	0	50	51	51
Transfers out of Level 3	(3)	(35)	(49)	(150)
Purchases	58	11	72	135
Sales	(24)	0	(28)	(22)
Issues	0	0	0	0
Settlements	0	(2)	(27)	(6)
Balance at end of period	82	78	82	78
MBS
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	45	35	40	26
Total gains (losses) included in: net income	0	0	1	0
Total gains (losses) included in: OCI	0	(1)	(1)	(1)
Transfers into Level 3	0	0	0	4
Transfers out of Level 3	0	0	0	0
Purchases	0	0	10	6
Sales	0	0	(4)	0
Issues	0	0	0	0
Settlements	(14)	0	(15)	(1)
Balance at end of period	31	34	31	34
Fixed income securities
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	371	286	342	325
Total gains (losses) included in: net income	0	1	1	0
Total gains (losses) included in: OCI	10	1	(5)	7
Transfers into Level 3	20	50	83	70
Transfers out of Level 3	(74)	(42)	(91)	(204)
Purchases	163	78	195	229
Sales	(38)	(3)	(42)	(46)
Issues	0	0	0	0
Settlements	(15)	(4)	(46)	(14)
Balance at end of period	437	367	437	367
Equity securities
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	393	319	371	341
Total gains (losses) included in: net income	2	11	(15)	49
Total gains (losses) included in: OCI	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	(1)	0	0	0
Purchases	3	55	42	77
Sales	(9)	0	(10)	(82)
Issues	0	0	0	0
Settlements	0	0	0	0
Balance at end of period	388	385	388	385
Short-term investments
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period	10	5	25	30
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	(25)	0
Purchases	20	10	30	25
Sales	0	0	0	(40)
Issues	0	0	0	0
Settlements	0	0	0	0
Balance at end of period	$ 30	15	$ 30	15
Free-standing derivatives, net
Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward
Balance at beginning of period		0		1
Total gains (losses) included in: net income		0		(1)
Total gains (losses) included in: OCI		0		0
Transfers into Level 3		0		0
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