Employee Retirement Plans and Postretirement Benefits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Pension plan contribution		$ 7.1	$ 8.2	$ 7.9
Benefits paid, including prescription drugs		33.8	33.0	37.6
Defined contribution plan, contribution during the period		77.8	75.5	$ 80.0
Pension
Defined Benefit Plan Disclosure [Line Items]
Curtailment, settlement or special termination benefit gain (loss)	$ 29.8
Accumulated benefit obligation		5,100.0	$ 5,600.0
Increase (decrease) in accumulated benefit obligation		240.8
Expected future employer contributions		4.0
Expected future benefit payment, next year		318.8
OPEB
Defined Benefit Plan Disclosure [Line Items]
Expected future benefit payment, next year		$ 41.4
U.S. defined contribution plans
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, contributions by employer, low end of the range (as a percent)		5.00%
Defined contribution plan, contributions by employer, high end of the range (as a percent)		11.00%
U.K. and Canadian defined contribution plans
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, contributions by employer, low end of the range (as a percent)		4.00%
Defined contribution plan, contributions by employer, high end of the range (as a percent)		10.00%
UK Pension Plan | Pension
Defined Benefit Plan Disclosure [Line Items]
Statutory valuation period		3 years
Canadian Defined Benefit Pension Plans | Pension
Defined Benefit Plan Disclosure [Line Items]
Expected surplus to be used for benefit payments		$ 5.0
UK defined contribution plan
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, contributions by employer, high end of the range (as a percent)		8.00%