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, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Allowance for credit losses:
Balance, beginning of period	$ 17	$ 22	$ 16	$ 1
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded	4	5	4	13
Available-for-sale securities accounted for as PCD assets	2	2	2	22
Reductions to the allowance for credit losses:
Securities sold during the period (realized)	0	0	4	6
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis	0	0	1	3
Write-offs charged against the allowance	9	15	9	15
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	4	4	10	6
Balance, end of period	18	18	18	18
Corporate and other bonds
Allowance for credit losses:
Balance, beginning of period	0	13	4	0
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded	4	5	4	6
Available-for-sale securities accounted for as PCD assets	2	2	2	22
Reductions to the allowance for credit losses:
Securities sold during the period (realized)	0	0	3	6
Intent to sell or more likely than not will be required to sell the security before recovery of its amortized cost basis	0	0	1	3
Write-offs charged against the allowance	0	15	0	15
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	0	0	1
Balance, end of period	6	5	6	5
Asset-backed
Allowance for credit losses:
Balance, beginning of period	17	9	12	1
Additions to the allowance for credit losses:
Securities for which credit losses were not previously recorded	0	0	0	7
Available-for-sale securities accounted for as PCD assets	0	0	0	0
Reductions to the allowance for credit losses:
Securities sold during the period (realized)	0	0	1	0
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	9	0	9	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	4	4	10	5
Balance, end of period	$ 12	$ 13	$ 12	$ 13