Investments - Composition of Current and Past Due Mortgage Loans on Real Estate (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Loans and Leases Receivable Disclosure [Line Items]
Allowance for credit losses	$ (133)	$ (114)
Unamortized premium (discount)	56	36
Mark-to-market gains (losses)	(34)	(38)
Total carrying value	20,152	18,963
Current
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	20,105	18,921
30 to 59 days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	30	89
60 to 89 days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	35	9
90 or more days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	93	60
Mark-to-market gains (losses)	30	1
Commercial
Loans and Leases Receivable Disclosure [Line Items]
Allowance for credit losses	(93)	(86)
Unamortized premium (discount)	(6)	(7)
Mark-to-market gains (losses)	(33)	(37)
Total carrying value	17,446	17,187
Commercial \| Current
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	17,522	17,256
Commercial \| 30 to 59 days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	0	61
Commercial \| 60 to 89 days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	22	0
Commercial \| 90 or more days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	34	0
Residential mortgage loans on real estate
Loans and Leases Receivable Disclosure [Line Items]
Allowance for credit losses	(40)	(28)
Unamortized premium (discount)	62	43
Mark-to-market gains (losses)	(1)	(1)
Total carrying value	2,706	1,776
Residential mortgage loans on real estate \| Current
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	2,583	1,665
Residential mortgage loans on real estate \| 30 to 59 days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	30	28
Residential mortgage loans on real estate \| 60 to 89 days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	13	9
Residential mortgage loans on real estate \| 90 or more days past due
Loans and Leases Receivable Disclosure [Line Items]
Mortgage loans on real estate, gross	$ 59	$ 60

This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of loans and long-term receivables (other than securities categorized as trading, available-for-sale or held-to-maturity) that have contractual principal amounts and for which the fair value option has been elected.

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