Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
ASU 2018-12
Tax at statutory rate (percentage):	21.00%	21.00%	21.00%
Release of unrecognized tax benefits during the year		$ 34
Income tax refund received	$ 2	0	$ 0
Net deferred tax assets, valuation allowance	0	31
United States
ASU 2018-12
Operating Loss Carryforwards	0	0
Cincinnati Global
ASU 2018-12
Net deferred tax assets, valuation allowance	0	31	$ 53	$ 56
Cincinnati Global | United States
ASU 2018-12
Operating Loss Carryforwards	0	5
Cincinnati Global | United Kingdom
ASU 2018-12
Operating Loss Carryforwards	$ 100	$ 109