Investments (Allowance on available-for-sale securities with credit impairments and PCD assets activity) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Allowance for credit losses:
Balance, beginning of period	$ 51	$ 17	$ 45	$ 16
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded	3	4	6	4
Available-for-sale securities accounted for as PCD assets	4	2	4	2
Reductions to the allowance for credit losses:
Securities disposed during the period (realized)	0	0	6	4
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis	0	0	0	1
Write-offs charged against the allowance	0	9	0	9
Recoveries of amounts previously written off	0	0	0	0
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period	3	4	12	10
Balance, end of period	61	18	61	18
Corporate and other bonds
Allowance for credit losses:
Balance, beginning of period	14	0	13	4
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded	0	4	3	4
Available-for-sale securities accounted for as PCD assets	4	2	4	2
Reductions to the allowance for credit losses:
Securities disposed during the period (realized)	0	0	6	3
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis	0	0	0	1
Write-offs charged against the allowance	0	0	0	0
Recoveries of amounts previously written off	0	0	0	0
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period	3	0	7	0
Balance, end of period	21	6	21	6
Asset-backed
Allowance for credit losses:
Balance, beginning of period	37	17	32	12
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded	3	0	3	0
Available-for-sale securities accounted for as PCD assets	0	0	0	0
Reductions to the allowance for credit losses:
Securities disposed during the period (realized)	0	0	0	1
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis	0	0	0	0
Write-offs charged against the allowance	0	9	0	9
Recoveries of amounts previously written off	0	0	0	0
Additional increases or (decreases) to the allowance for credit losses on securities that had an allowance recorded in a previous period	0	4	5	10
Balance, end of period	$ 40	$ 12	$ 40	$ 12