Investments (Past Due Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	$ 19,910	$ 15,816
Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	19,837	15,741
30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	14	9
60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	14	24
90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	29	27
180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	16	15
Commercial
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	12,159	9,687
Commercial | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	12,159	9,687
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	0	0
Agricultural
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,128	3,479
Agricultural | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	4,128	3,479
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	0
Agricultural | 180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	0	0
Residential
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	3,623	2,650
Residential | Current
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	3,550	2,575
Residential | 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	14	9
Residential | 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	14	24
Residential | 90 to 179 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	29	27
Residential | 180 Days and Greater Past Due
Financing Receivable, Past Due [Line Items]
Financing receivable, before allowance for credit losses	$ 16	$ 15