Investments (Amortized Cost and Fair Value of Fixed Maturity Holdings by Industry Type) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Corporate Securities by Investment Sector And Credit Rating [Line Items]
Amortized Cost	$ 57,849	$ 55,873
Fixed maturity securities, available-for-sale	57,922	60,749
Corporate Debt Securities [Member]
Corporate Securities by Investment Sector And Credit Rating [Line Items]
Amortized Cost	36,813	35,239
Fixed maturity securities, available-for-sale	$ 36,380	$ 38,103
% of Total	100.00%	100.00%
Corporate Debt Securities [Member] | Finance
Corporate Securities by Investment Sector And Credit Rating [Line Items]
Amortized Cost	$ 13,839	$ 13,101
Fixed maturity securities, available-for-sale	$ 13,599	$ 14,045
% of Total	37.40%	36.90%
Corporate Debt Securities [Member] | Industrial
Corporate Securities by Investment Sector And Credit Rating [Line Items]
Amortized Cost	$ 18,496	$ 17,857
Fixed maturity securities, available-for-sale	$ 18,382	$ 19,375
% of Total	50.50%	50.80%
Corporate Debt Securities [Member] | Utility
Corporate Securities by Investment Sector And Credit Rating [Line Items]
Amortized Cost	$ 4,478	$ 4,281
Fixed maturity securities, available-for-sale	$ 4,399	$ 4,683
% of Total	12.10%	12.30%