Investments (Mortgage Loans by Maturity Date) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 7,633	$ 7,459
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	100.00%	100.00%
Due within five years
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 3,463	$ 3,228
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	45.40%	43.30%
Due after five years through ten years
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 3,321	$ 3,334
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	43.50%	44.70%
Due after ten years
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 849	$ 897
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	11.10%	12.00%