Retirement Benefit Plans - Balance Sheet (Details) - Accrued pension cost - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Amounts recognized on the Consolidated Balance Sheets:
Current liabilities	$ (6.3)	$ (15.7)
U.S. Plans
Amounts recognized on the Consolidated Balance Sheets:
Non-current assets	1.1	1.8
Current liabilities	(4.9)	(14.2)
Non-current liabilities	(106.8)	(97.4)
Total	(110.6)	(109.8)
International Plans
Amounts recognized on the Consolidated Balance Sheets:
Non-current assets	3.9	0.2
Current liabilities	(1.4)	(1.5)
Non-current liabilities	(48.8)	(65.6)
Total	$ (46.3)	$ (66.9)