Investments (Exposure To Concentrations Of Credit Risk) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	$ 57,849	$ 55,873
Fixed maturity securities, available-for-sale	57,922	60,749
Government Of Japan [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	3,887	3,080
Fixed maturity securities, available-for-sale	3,742	3,063
Canadian Province Of Quebec Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,409	1,377
Fixed maturity securities, available-for-sale	2,062	2,347
Canadian Province Of Ontario Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,063	1,092
Fixed maturity securities, available-for-sale	$ 1,288	$ 1,451