Insurance Claim Reserves Insurance Claim Reserves (Details) - Asbestos and Environmental Reserves - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Liability for claims and claim adjustment expense
Asbestos and environmental claims reserves, balance	$ 1,760	$ 1,680
Asbestos reserves [Member]
Liability for claims and claim adjustment expense
Increase to reserves	284	212	$ 225
Net losses paid	$ 212	$ 245	$ 221
Percent of total asbestos net paid losses related to policyholders with whom the Company had entered into settlement agreements limiting the Company's liability	1.00%	2.00%	9.00%
Environmental reserves [Member]
Liability for claims and claim adjustment expense
Increase to reserves	$ 93	$ 132	$ 89