Investments - Changes in Allowance for Credit Losses on Mortgage Loans on Real Estate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	$ 98,000,000
Balance as of end-of-year	114,000,000	$ 98,000,000
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	83,000,000
Balance as of end-of-year	86,000,000	83,000,000
Residential
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	15,000,000
Balance as of end-of-year	28,000,000	15,000,000
Mortgage loans on real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	98,000,000	95,000,000	$ 203,000,000
Additions (reductions) from provision for credit loss expense	16,000,000	3,000,000	(108,000,000)
Additions from purchases of PCD mortgage loans on real estate	0	0	0
Balance as of end-of-year	114,000,000	98,000,000	95,000,000
Credit loss expense (reversal)	(1,000,000)	0	3,000,000
Accrued interest receivable excluded from credit losses	67,000,000	51,000,000	48,000,000
Mortgage loans on real estate | Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	83,000,000	78,000,000	186,000,000
Additions (reductions) from provision for credit loss expense	3,000,000	5,000,000	(108,000,000)
Additions from purchases of PCD mortgage loans on real estate	0	0	0
Balance as of end-of-year	86,000,000	83,000,000	78,000,000
Mortgage loans on real estate | Residential
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	15,000,000	17,000,000	17,000,000
Additions (reductions) from provision for credit loss expense	13,000,000	(2,000,000)	0
Additions from purchases of PCD mortgage loans on real estate	0	0	0
Balance as of end-of-year	$ 28,000,000	$ 15,000,000	$ 17,000,000