Stockholders' Equity and Statutory Accounting Practices (Combined statutory capital and surplus and net income (loss)) (Details) - Combined Continental Casualty Companies - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statutory Accounting Practices [Line Items]
Statutory Capital and Surplus	$ 11,321	$ 10,708
Statutory Net Income (Loss)	$ 1,253	$ 800	$ 1,062