Retirement Benefits - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) benefit_plan	Dec. 31, 2020 USD ($) benefit_plan	Dec. 31, 2019 USD ($) benefit_plan
Defined Benefit Plan Disclosure [Line Items]
Number of defined contribution pension plans | benefit_plan	4
Defined contribution pension plans, total costs	$ 23.3	$ 21.0	$ 20.8
Number of multiemployer defined benefit pension plans | benefit_plan	1	1	1
Multiemployer plan total employer contributions	$ 0.2	$ 0.2	$ 0.2
Restructuring charges	$ 3.9	$ 20.4	28.8
Futures contract supported by cash or cash equivalents	100.00%
United States
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.90%	2.60%
United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.80%	1.40%
Canada
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.98%	2.55%
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Settlement loss	$ 7.6
Benefit obligation	937.7	$ 994.2	938.7
Accumulated benefit obligation	937.6	993.9
Settlement of multi-employer pension plan	$ 5.0	$ 6.0	$ 10.0
Discount rate	2.79%	2.47%	3.17%
Employer contributions	$ 7.9	$ 29.5
Pension Benefits | United States
Defined Benefit Plan Disclosure [Line Items]
Curtailment loss			$ 0.3
Defined benefit obligation per plan, as a percent of total benefit obligation	87.00%
Pension Benefits | Qualified Plan | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 0.1
Company Stock
Defined Benefit Plan Disclosure [Line Items]
Employer stock included in plan assets	$ 0.0	$ 0.0