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Investments - Available for sale fixed maturities (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	$ 10,583	$ 10,736
Fixed maturities, available for sale, allowance for expected credit losses	16	11	$ 7	$ 9
Available for sale (AFS) fixed maturities	10,044	10,095
Total fixed maturities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	10,583	10,736
Fixed maturities, available for sale, allowance for expected credit losses	16	11
Fixed maturities, available for sale, gross unrealized, gains	54	39
Fixed maturities, available for sale, gross unrealized, losses	(577)	(669)
Available for sale (AFS) fixed maturities	10,044	10,095
Total fixed maturities \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(523)	(630)
U.S. government and government agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	236	233
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Fixed maturities, available for sale, gross unrealized, gains	0	0
Fixed maturities, available for sale, gross unrealized, losses	(11)	(14)
Available for sale (AFS) fixed maturities	225	219
U.S. government and government agencies \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(11)	(14)
States, municipalities and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	1,024	1,234
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Fixed maturities, available for sale, gross unrealized, gains	4	3
Fixed maturities, available for sale, gross unrealized, losses	(35)	(51)
Available for sale (AFS) fixed maturities	993	1,186
States, municipalities and political subdivisions \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(31)	(48)
Foreign government
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	238	240
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Fixed maturities, available for sale, gross unrealized, gains	0	0
Fixed maturities, available for sale, gross unrealized, losses	(12)	(14)
Available for sale (AFS) fixed maturities	226	226
Foreign government \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(12)	(14)
Residential MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	1,743	1,757
Fixed maturities, available for sale, allowance for expected credit losses	2	2
Fixed maturities, available for sale, gross unrealized, gains	23	23
Fixed maturities, available for sale, gross unrealized, losses	(175)	(180)
Available for sale (AFS) fixed maturities	1,589	1,598
Residential MBS \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(152)	(157)
Commercial MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	80	88
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Fixed maturities, available for sale, gross unrealized, gains	0	0
Fixed maturities, available for sale, gross unrealized, losses	(2)	(3)
Available for sale (AFS) fixed maturities	78	85
Commercial MBS \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(2)	(3)
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	1,950	1,988
Fixed maturities, available for sale, allowance for expected credit losses	1	1
Fixed maturities, available for sale, gross unrealized, gains	3	1
Fixed maturities, available for sale, gross unrealized, losses	(53)	(67)
Available for sale (AFS) fixed maturities	1,899	1,921
Collateralized loan obligations \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(50)	(66)
Other asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	2,395	2,435
Fixed maturities, available for sale, allowance for expected credit losses	8	7
Fixed maturities, available for sale, gross unrealized, gains	2	1
Fixed maturities, available for sale, gross unrealized, losses	(148)	(184)
Available for sale (AFS) fixed maturities	2,241	2,245
Other asset-backed securities \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	(146)	(183)
Corporate and other
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available for sale, amortized cost	2,917	2,761
Fixed maturities, available for sale, allowance for expected credit losses	5	1	$ 1	$ 1
Fixed maturities, available for sale, gross unrealized, gains	22	11
Fixed maturities, available for sale, gross unrealized, losses	(141)	(156)
Available for sale (AFS) fixed maturities	2,793	2,615
Corporate and other \| Debt Securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale securities, accumulated gross unrealized gain (loss), before tax	$ (119)	$ (145)