Income Taxes, Current and Deferred Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Taxes [Abstract]
Notice period for cancellation of agreement	30 days
Federal [Abstract]
Current	$ 239	$ 43	$ 108
Deferred	197	(260)	47
State and Local Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current	13	1	18
Deferred	13	13	22
Foreign	17	30	53
Income tax expense (benefit)	$ 479	$ (173)	$ 248
Non-insurance warranty – CNA Financial | Minimum
Income Taxes [Abstract]
Percentage of equity method investments in associated companies	80.00%