Investments (Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 19,910	$ 15,816
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	$ (123)	$ (94)	$ (64)
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	$ 19,787	$ 15,722
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	$ 12,159	$ 9,687
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	61.40%	61.60%
Financing receivable, allowance for credit losses	$ (67)	$ (44)	(47)
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 4,128	$ 3,479
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	20.90%	22.10%
Financing receivable, allowance for credit losses	$ (12)	$ (15)	(10)
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 3,623	$ 2,650
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	18.30%	16.90%
Financing receivable, allowance for credit losses	$ (44)	$ (35)	$ (7)