Investments (Past Due Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	$ 22,924	$ 22,996
Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	22,828	22,902
30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	19	11
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	35	16
90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	6	34
180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	36	33
Commercial
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	13,525	13,547
Commercial | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	13,508	13,547
Commercial | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	17	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	0	0
Agricultural
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,357	4,333
Agricultural | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,351	4,314
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	4	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	2	16
Residential
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	5,042	5,116
Residential | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,969	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	31	16
Residential | 90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	6	31
Residential | 180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	$ 34	$ 17