Investments (Mortgage Loans by Portfolio Segment) (Details) - Mortgage Loans - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 23,039	$ 23,432
Financing receivable, allowance for credit losses	(205)	(178)	$ (167)	$ (137)
Financing receivable, net of allowance for credit losses	$ 22,834	$ 23,254
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	100.90%	100.70%
Financing receivable, allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	(0.90%)	(0.70%)
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	$ 12,631	$ 13,326
Financing receivable, allowance for credit losses	$ (143)	$ (106)	(95)	(69)
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	55.30%	57.30%
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, before allowance for credit losses	$ 4,541	$ 4,563
Financing receivable, allowance for credit losses	$ (21)	$ (30)	(30)	(19)
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	$ 5,867	$ 5,543
Financing receivable, allowance for credit losses	$ (41)	$ (42)	$ (42)	$ (49)
Financing receivable, before allowance for credit losses as a percentage of financing receivable, net of allowance for credit losses	25.70%	23.80%