Investments (Exposure To Concentrations Of Credit Risk) (Details) - USD ($) $ in Millions	Mar. 31, 2024		Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	$ 70,790		$ 64,977
Fixed maturity securities, available-for-sale	65,827	[1]	60,467	[2]
Canadian Province Of Quebec Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,454		1,467
Fixed maturity securities, available-for-sale	1,636		1,748
Canadian Province Of Ontario Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available for Sale at Fair value - Amortized cost	1,002		1,019
Fixed maturity securities, available-for-sale	$ 1,070		$ 1,125

[1] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of March 31, 2024, the fair value of such investments was $893 million.

[2] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of December 31, 2023, the fair value of such investments was $856 million