Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Income Tax Contingency
Tax at statutory rate, percentage	21.00%	21.00%	21.00%	21.00%
Deferred tax assets valuation allowance	$ 0		$ 0		$ 0
Cincinnati Global
Income Tax Contingency
Decrease in deferred tax assets	5		10
Decrease in deferred tax valuation allowance	5		10
Net deferred tax assets	21		21
Deferred tax assets valuation allowance	21		21
Cincinnati Global | United States
Income Tax Contingency
Operating loss carryforwards	6		6		5
Cincinnati Global | United Kingdom
Income Tax Contingency
Operating loss carryforwards	$ 101		$ 101		$ 109