Retirement Benefit Plans - Narrative (Details) $ in Millions	3 Months Ended					12 Months Ended
	Dec. 31, 2022 USD ($) shares	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2023	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Company contributions / payments							$ 11.2	$ 20.4	$ 17.9
Actuarial losses	$ (12.3)	$ 11.6	$ (8.0)	$ 3.9	$ 3.5
Return on plan assets							$ 29.4	27.3	27.1
Company common stock (in shares) | shares	682,831						682,831
Fair value of company common stock	$ 48.3						$ 48.3
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Company contributions / payments							11.2	20.4
Actuarial losses							16.0	4.4	16.2
Accumulated benefit obligations	539.9						539.9
Current liabilities	6.3		6.3				6.3	6.3
Projected benefit obligation	544.2						544.2
Fair value of plan assets	378.0						378.0
Pension accumulated benefit obligation	546.0		897.6				$ 546.0	897.6
Percentage increase in value (as a percent)							26.70%
Defined benefit plan, plan assets, amount	387.1		752.5				$ 387.1	752.5
Pension Plan | Return on Plan Assets vs. Expectation
Defined Benefit Plan Disclosure [Line Items]
Recognition of net actuarial (gains) losses							220.6	28.4	84.3
Pension Plan | Experience Losses Impact
Defined Benefit Plan Disclosure [Line Items]
Recognition of net actuarial (gains) losses							33.0	9.3	$ 16.9
Pension Plan | Inflation Impact
Defined Benefit Plan Disclosure [Line Items]
Recognition of net actuarial (gains) losses							5.4	8.5
Pension Plan | Other Actuarial Assumptions
Defined Benefit Plan Disclosure [Line Items]
Recognition of net actuarial (gains) losses							(0.2)	3.2
Pension Plan | Discount Rate Increase
Defined Benefit Plan Disclosure [Line Items]
Recognition of net actuarial (gains) losses							243.2	45.0
Pension Plan | Discount Rate in Basis Points
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) to discount rate (basis points)									0.0066
Pension Plan | Discount Rate in Dollars
Defined Benefit Plan Disclosure [Line Items]
Recognition of net actuarial (gains) losses									$ 88.0
Pension Plan | Other Valuation Assumptions
Defined Benefit Plan Disclosure [Line Items]
Recognition of net actuarial (gains) losses									4.4
Pension Plan | Overfunded Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligations	$ 0.3		$ 5.0				0.3	5.0
Pension Plan | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Company contributions / payments							5.2	17.0
Deferred compensation								10.0
Actuarial losses							(116.4)	(4.4)
Recognition of net actuarial (gains) losses							$ (22.6)	$ (13.9)	$ 3.9
Discount rate (as a percent)	5.64%		3.07%				5.64%	3.07%	2.84%	3.50%
Discount rate (as a percent)							3.07%
Expected long-term return on plan assets (as a percent)							4.84%
Percentage of defined benefit plan obligation in US (as a percent)							61.00%
Defined benefit pension plan percentage of fair value of plan assets (as a percent)							52.00%
Current liabilities	$ 4.8		$ 4.9				$ 4.8	$ 4.9
Defined benefit plan, plan assets, amount	$ 201.6		$ 455.7				$ 201.6	$ 455.7	$ 553.3
Pension Plan | U.S. Plans | Forecast
Defined Benefit Plan Disclosure [Line Items]
Discount rate (as a percent)						5.64%
Expected long-term return on plan assets (as a percent)						4.43%
Pension Plan | U.S. Plans | Discount Rate in Basis Points
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) to discount rate (basis points)							0.0257	0.0023
Pension Plan | International Plans
Defined Benefit Plan Disclosure [Line Items]
Company contributions / payments							$ 6.0	$ 3.4
Actuarial losses							(88.2)	(19.6)
Recognition of net actuarial (gains) losses							$ 6.6	$ 9.5	$ (20.1)
Discount rate (as a percent)	4.81%		1.80%				4.81%	1.80%	1.25%
Current liabilities	$ 1.5		$ 1.4				$ 1.5	$ 1.4
Defined benefit plan, plan assets, amount	185.5		296.8				$ 185.5	$ 296.8	$ 312.8
Pension Plan | International Plans | Discount Rate in Basis Points
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) to discount rate (basis points)							0.0301	0.0055
Pension Plan | International Plans | Fair Value, Recurring
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, plan assets, amount	$ 155.0		$ 253.5				$ 155.0	$ 253.5
Employee Stock
Defined Benefit Plan Disclosure [Line Items]
Dividends							$ 1.0	$ 1.2	$ 1.5