Income Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle
Unrecognized Tax Benefits	$ 34	$ 34	$ 34
Income taxes refund received	0	0	94
Net deferred tax assets, valuation allowance	53	56
United States
New Accounting Pronouncements or Change in Accounting Principle
Operating Loss Carryforwards	0	0
Cincinnati Global
New Accounting Pronouncements or Change in Accounting Principle
Net deferred tax assets	53
Net deferred tax assets, valuation allowance	53	56	41	$ 0
Decrease of deferred tax asset valuation allowance	(3)	15	$ (14)
Cincinnati Global
New Accounting Pronouncements or Change in Accounting Principle
Decrease of deferred tax assets	3
Decrease of deferred tax asset valuation allowance	3
Cincinnati Global | United Kingdom
New Accounting Pronouncements or Change in Accounting Principle
Operating Loss Carryforwards	130	108
Cincinnati Global | United States
New Accounting Pronouncements or Change in Accounting Principle
Operating Loss Carryforwards	$ 8	$ 26