Investments (Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 21,422	$ 19,910
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	100.60%	100.60%
Financing receivable, allowance for credit losses	$ (127)	$ (123)	$ (90)	$ (94)
Financing receivable, allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	(0.60%)	(0.60%)
Financing receivable, net of allowance for credit losses	$ 21,295	$ 19,787
Financing receivable, after allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	100.00%	100.00%
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 13,092	$ 12,159
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	61.50%	61.40%
Financing receivable, allowance for credit losses	$ (69)	$ (67)	(45)	(44)
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 4,104	$ 4,128
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	19.30%	20.90%
Financing receivable, allowance for credit losses	$ (15)	$ (12)	(13)	(15)
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 4,226	$ 3,623
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	19.80%	18.30%
Financing receivable, allowance for credit losses	$ (43)	$ (44)	$ (32)	$ (35)