Investments - Changes in Allowance for Credit Losses on Mortgage Loans on Real Estate (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	$ 114
Balance as of end-of-period	115
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	86
Balance as of end-of-period	84
Residential
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	28
Balance as of end-of-period	31
Mortgage loans on real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	114	$ 98
Additions (reductions) from provision for credit loss expense	1	5
Additions from purchases of PCD mortgage loans on real estate	0	0
Balance as of end-of-period	115	103
Credit loss expense (reversal)	1	1
Accrued investment income excluded from credit losses	69	52
Mortgage loans on real estate | Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	86	83
Additions (reductions) from provision for credit loss expense	(2)	0
Additions from purchases of PCD mortgage loans on real estate	0	0
Balance as of end-of-period	84	83
Mortgage loans on real estate | Residential
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance as of beginning-of-year	28	15
Additions (reductions) from provision for credit loss expense	3	5
Additions from purchases of PCD mortgage loans on real estate	0	0
Balance as of end-of-period	$ 31	$ 20