Investments - Available for sale fixed maturities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	$ 10,752	$ 10,736
Fixed maturities, available for sale, allowance for expected credit losses	12	11	$ 9	$ 12
Available for sale (AFS) fixed maturities	10,377	10,095
Total fixed maturities
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	10,752	10,736
Fixed maturities, available for sale, allowance for expected credit losses	12	11
Gross unrealized gains on available for sale fixed maturities	107	39
Gross unrealized losses on available for sale fixed maturities	(470)	(669)
Net unrealized gain (loss) on available for sale fixed maturities	(363)	(630)
Available for sale (AFS) fixed maturities	10,377	10,095
U.S. Government and government agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	243	233
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Gross unrealized gains on available for sale fixed maturities	1	0
Gross unrealized losses on available for sale fixed maturities	(8)	(14)
Net unrealized gain (loss) on available for sale fixed maturities	(7)	(14)
Available for sale (AFS) fixed maturities	236	219
States, municipalities and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	1,014	1,234
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Gross unrealized gains on available for sale fixed maturities	8	3
Gross unrealized losses on available for sale fixed maturities	(38)	(51)
Net unrealized gain (loss) on available for sale fixed maturities	(30)	(48)
Available for sale (AFS) fixed maturities	984	1,186
Foreign government
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	236	240
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Gross unrealized gains on available for sale fixed maturities	1	0
Gross unrealized losses on available for sale fixed maturities	(7)	(14)
Net unrealized gain (loss) on available for sale fixed maturities	(6)	(14)
Available for sale (AFS) fixed maturities	230	226
Residential MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	1,788	1,757
Fixed maturities, available for sale, allowance for expected credit losses	1	2
Gross unrealized gains on available for sale fixed maturities	26	23
Gross unrealized losses on available for sale fixed maturities	(155)	(180)
Net unrealized gain (loss) on available for sale fixed maturities	(129)	(157)
Available for sale (AFS) fixed maturities	1,658	1,598
Commercial MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	75	88
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Gross unrealized gains on available for sale fixed maturities	0	0
Gross unrealized losses on available for sale fixed maturities	(1)	(3)
Net unrealized gain (loss) on available for sale fixed maturities	(1)	(3)
Available for sale (AFS) fixed maturities	74	85
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	1,709	1,988
Fixed maturities, available for sale, allowance for expected credit losses	3	1
Gross unrealized gains on available for sale fixed maturities	9	1
Gross unrealized losses on available for sale fixed maturities	(28)	(67)
Net unrealized gain (loss) on available for sale fixed maturities	(19)	(66)
Available for sale (AFS) fixed maturities	1,687	1,921
Other asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	2,477	2,435
Fixed maturities, available for sale, allowance for expected credit losses	5	7
Gross unrealized gains on available for sale fixed maturities	10	1
Gross unrealized losses on available for sale fixed maturities	(120)	(184)
Net unrealized gain (loss) on available for sale fixed maturities	(110)	(183)
Available for sale (AFS) fixed maturities	2,362	2,245
Corporate and other
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	3,210	2,761
Fixed maturities, available for sale, allowance for expected credit losses	3	1	$ 1	$ 2
Gross unrealized gains on available for sale fixed maturities	52	11
Gross unrealized losses on available for sale fixed maturities	(113)	(156)
Net unrealized gain (loss) on available for sale fixed maturities	(61)	(145)
Available for sale (AFS) fixed maturities	$ 3,146	$ 2,615

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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