Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Income Tax Contingency
Tax at statutory rate, percentage	21.00%	21.00%
Deferred tax assets valuation allowance	$ 0		$ 0
Cincinnati Global
Income Tax Contingency
Deferred tax assets valuation allowance	26
Decrease in deferred tax assets	5
Decrease in deferred tax valuation allowance	5
Net deferred tax assets	26
Cincinnati Global | United States
Income Tax Contingency
Operating loss carryforwards	6		5
Cincinnati Global | United Kingdom
Income Tax Contingency
Operating loss carryforwards	$ 105		$ 109