Investments (Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 22,776	$ 22,612
Financing receivable, allowance for credit losses	(142)	(137)	$ (136)	$ (119)
Financing receivable, net of allowance for credit losses	$ 22,634	$ 22,475
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 as a percentage of financing receivable, net of allowance for credit losses	(0.60%)	(0.60%)
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	$ 13,204	$ 13,189
Financing receivable, allowance for credit losses	$ (78)	$ (69)	(64)	(49)
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	58.30%	58.70%
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 4,507	$ 4,416
Financing receivable, allowance for credit losses	$ (19)	$ (19)	(14)	(15)
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	19.90%	19.60%
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 5,065	$ 5,007
Financing receivable, allowance for credit losses	$ (45)	$ (49)	$ (58)	$ (55)
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	22.40%	22.30%