Investments (Past Due Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	$ 22,645	$ 23,055
Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	22,520	22,961
30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	2	11
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	30	16
90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	23	34
180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	70	33
Commercial
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	13,193	13,574
Commercial | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	13,176	13,574
Commercial | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	0	0
Commercial | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	0	0
Commercial | 90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	0	0
Commercial | 180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	17	0
Agricultural
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,445	4,365
Agricultural | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,429	4,346
Agricultural | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	0	0
Agricultural | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	0	0
Agricultural | 90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	0	3
Agricultural | 180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	16	16
Residential
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	5,007	5,116
Residential | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,915	5,041
Residential | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	2	11
Residential | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	30	16
Residential | 90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	23	31
Residential | 180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	$ 37	$ 17