Fair Value of Assets and Liabilities - Rollforward of level 3 assets and liabilities held at fair value (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Balance at beginning of period	$ 738	$ 697	$ 837
Total gains (losses) included in: net income	0	30	37
Total gains (losses) included in: OCI	(12)	6	(6)
Transfers into Level 3	128	158	79
Transfers out of Level 3	(116)	(330)	(325)
Purchases	240	375	367
Sales	(95)	(173)	(208)
Issues	0	0	0
Settlements	(51)	(25)	(84)
Balance at end of period	832	738	697
Liabilities
Balance at beginning of period	(462)	(224)	(286)
Total gains (losses) included in: net income	(43)	(61)	58
Total gains (losses) included in: OCI	0	0	0
Transfers into Level 3	0	(175)	0
Transfers out of Level 3	0	0	0
Purchases	0	0	0
Sales	0	0	0
Issues	(34)	(16)	(2)
Settlements	23	14	6
Balance at end of period	(516)	(462)	(224)
Fair value assets and liabilities measured on recurring basis, gain (loss) included in earnings
Gain (loss) included in earnings	(43)	(31)	95
Net investment income
Assets
Total gains (losses) included in: net income	(23)	(2)	0
Realized capital gains (losses)
Assets
Total gains (losses) included in: net income	23	32	37
Life contract benefits
Assets
Total gains (losses) included in: net income	(1)	7	(5)
Interest credited to contractholder funds
Assets
Total gains (losses) included in: net income	(42)	(68)	63
Contractholder funds: Derivatives embedded in life and annuity contracts
Liabilities
Balance at beginning of period	(462)	(224)	(286)
Total gains (losses) included in: net income	(43)	(61)	58
Total gains (losses) included in: OCI	0	0	0
Transfers into Level 3	0	(175)	0
Transfers out of Level 3	0	0	0
Purchases	0	0	0
Sales	0	0	0
Issues	(34)	(16)	(2)
Settlements	23	14	6
Balance at end of period	(516)	(462)	(224)
Municipal
Assets
Balance at beginning of period	62	70	101
Total gains (losses) included in: net income	1	1	1
Total gains (losses) included in: OCI	2	4	(2)
Transfers into Level 3	20	0	0
Transfers out of Level 3	(11)	(5)	(26)
Purchases	0	0	10
Sales	(4)	(5)	(8)
Issues	0	0	0
Settlements	(3)	(3)	(6)
Balance at end of period	67	62	70
Corporate - public
Assets
Balance at beginning of period	61	70	108
Total gains (losses) included in: net income	(1)	0	0
Total gains (losses) included in: OCI	1	3	(3)
Transfers into Level 3	2	30	17
Transfers out of Level 3	0	(113)	(21)
Purchases	55	86	10
Sales	(19)	(11)	(38)
Issues	0	0	0
Settlements	(1)	(4)	(3)
Balance at end of period	98	61	70
Corporate - privately placed
Assets
Balance at beginning of period	114	90	224
Total gains (losses) included in: net income	2	(1)	(1)
Total gains (losses) included in: OCI	(12)	2	(3)
Transfers into Level 3	52	43	20
Transfers out of Level 3	(31)	(2)	(119)
Purchases	25	4	22
Sales	(17)	(13)	(5)
Issues	0	0	0
Settlements	(3)	(9)	(48)
Balance at end of period	130	114	90
ABS
Assets
Balance at beginning of period	65	69	147
Total gains (losses) included in: net income	0	1	0
Total gains (losses) included in: OCI	(1)	(1)	2
Transfers into Level 3	54	76	42
Transfers out of Level 3	(49)	(210)	(159)
Purchases	48	159	160
Sales	(32)	(22)	(97)
Issues	0	0	0
Settlements	(28)	(7)	(26)
Balance at end of period	57	65	69
MBS
Assets
Balance at beginning of period	40	26	26
Total gains (losses) included in: net income	1	0	0
Total gains (losses) included in: OCI	(2)	(2)	0
Transfers into Level 3	0	9	0
Transfers out of Level 3	0	0	0
Purchases	11	9	1
Sales	(7)	0	0
Issues	0	0	0
Settlements	(16)	(2)	(1)
Balance at end of period	27	40	26
Fixed income securities
Assets
Balance at beginning of period	342	325	606
Total gains (losses) included in: net income	3	1	0
Total gains (losses) included in: OCI	(12)	6	(6)
Transfers into Level 3	128	158	79
Transfers out of Level 3	(91)	(330)	(325)
Purchases	139	258	203
Sales	(79)	(51)	(148)
Issues	0	0	0
Settlements	(51)	(25)	(84)
Balance at end of period	379	342	325
Equity securities
Assets
Balance at beginning of period	371	341	210
Total gains (losses) included in: net income	(3)	30	37
Total gains (losses) included in: OCI	0	0	0
Transfers into Level 3	0	0	0
Transfers out of Level 3	0	0	0
Purchases	66	82	109
Sales	(16)	(82)	(15)
Issues	0	0	0
Settlements	0	0	0
Balance at end of period	418	371	341
Short-term investments
Assets
Balance at beginning of period	25	30	20
Total gains (losses) included in: net income	0	0	0
Total gains (losses) included in: OCI	0	0	0
Transfers into Level 3	0	0	0
Transfers out of Level 3	(25)	0	0
Purchases	35	35	55
Sales	0	(40)	(45)
Issues	0	0	0
Settlements	0	0	0
Balance at end of period	35	25	30
Free-standing derivatives, net
Assets
Balance at beginning of period	$ 0	1	1
Total gains (losses) included in: net income		(1)	0
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	$ 1

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Amount of gain (loss) recognized in income from asset and liability measured at fair value on recurring basis using unobservable input (level 3).

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Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy.

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Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

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Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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