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, 2023	Dec. 31, 2022	Dec. 31, 2021
Statutory Accounting Practices [Line Items]
Statutory Capital and Surplus	$ 10,946	$ 10,572
Statutory Net Income (Loss)	$ 1,172	$ 1,072	$ 1,253