Investments (Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 22,785	$ 22,996
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	100.60%	100.50%
Financing receivable, allowance for credit losses	$ (137)	$ (119)	$ (99)	$ (123)
Financing receivable, allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	(0.60%)	(0.50%)
Financing receivable, net of allowance for credit losses	$ 22,648	$ 22,877
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	$ 13,303	$ 13,547
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	58.70%	59.20%
Financing receivable, allowance for credit losses	$ (67)	$ (49)	(45)	(67)
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 4,431	$ 4,333
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	19.60%	18.90%
Financing receivable, allowance for credit losses	$ (15)	$ (15)	(15)	(12)
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 5,051	$ 5,116
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	22.30%	22.40%
Financing receivable, allowance for credit losses	$ (55)	$ (55)	$ (39)	$ (44)