Investments - Available for sale fixed maturities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	$ 10,687	$ 10,752
Fixed maturities, available for sale, allowance for expected credit losses	34	12	$ 11	$ 9
Available for sale (AFS) fixed maturities	10,398	10,377
Total fixed maturities
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	10,687	10,752
Fixed maturities, available for sale, allowance for expected credit losses	34	12
Gross unrealized gains on available for sale fixed maturities	98	107
Gross unrealized losses on available for sale fixed maturities	(353)	(470)
Net unrealized gain (loss) on available for sale fixed maturities	(255)	(363)
Available for sale (AFS) fixed maturities	10,398	10,377
U.S. Government and government agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	176	243
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Gross unrealized gains on available for sale fixed maturities	0	1
Gross unrealized losses on available for sale fixed maturities	(3)	(8)
Net unrealized gain (loss) on available for sale fixed maturities	(3)	(7)
Available for sale (AFS) fixed maturities	173	236
States, municipalities and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	905	1,014
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Gross unrealized gains on available for sale fixed maturities	3	8
Gross unrealized losses on available for sale fixed maturities	(49)	(38)
Net unrealized gain (loss) on available for sale fixed maturities	(46)	(30)
Available for sale (AFS) fixed maturities	859	984
Foreign government
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	236	236
Fixed maturities, available for sale, allowance for expected credit losses	0	0
Gross unrealized gains on available for sale fixed maturities	2	1
Gross unrealized losses on available for sale fixed maturities	(1)	(7)
Net unrealized gain (loss) on available for sale fixed maturities	1	(6)
Available for sale (AFS) fixed maturities	237	230
Residential MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	2,122	1,788
Fixed maturities, available for sale, allowance for expected credit losses	1	1
Gross unrealized gains on available for sale fixed maturities	22	26
Gross unrealized losses on available for sale fixed maturities	(154)	(155)
Net unrealized gain (loss) on available for sale fixed maturities	(132)	(129)
Available for sale (AFS) fixed maturities	1,989	1,658
Commercial MBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	51	75
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	0	(1)
Net unrealized gain (loss) on available for sale fixed maturities	0	(1)
Available for sale (AFS) fixed maturities	51	74
Collateralized loan obligations
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	1,243	1,709
Fixed maturities, available for sale, allowance for expected credit losses	4	3
Gross unrealized gains on available for sale fixed maturities	10	9
Gross unrealized losses on available for sale fixed maturities	(12)	(28)
Net unrealized gain (loss) on available for sale fixed maturities	(2)	(19)
Available for sale (AFS) fixed maturities	1,237	1,687
Other asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	2,412	2,477
Fixed maturities, available for sale, allowance for expected credit losses	6	5
Gross unrealized gains on available for sale fixed maturities	19	10
Gross unrealized losses on available for sale fixed maturities	(69)	(120)
Net unrealized gain (loss) on available for sale fixed maturities	(50)	(110)
Available for sale (AFS) fixed maturities	2,356	2,362
Corporate and other
Debt Securities, Available-for-sale [Line Items]
Fixed maturies, available for sale, amortized cost	3,542	3,210
Fixed maturities, available for sale, allowance for expected credit losses	23	3	$ 1	$ 1
Gross unrealized gains on available for sale fixed maturities	42	52
Gross unrealized losses on available for sale fixed maturities	(65)	(113)
Net unrealized gain (loss) on available for sale fixed maturities	(23)	(61)
Available for sale (AFS) fixed maturities	$ 3,496	$ 3,146

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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