Employee Benefits - Summary of Total Expense (Benefit) Related to All Postretirement Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Total net periodic postretirement benefit cost	$ 1.5	$ 1.2	$ 2.9	$ 1.8
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	4.0	3.6	9.7	7.0
Deferred compensation arrangement with individual, compensation expense	(0.5)	0.4	(0.8)	0.4
Multiemployer plan, contributions by employer	1.4	1.3	2.6	2.4
Total net periodic postretirement benefit cost	1.0	1.0	1.9	1.0
Total other employee benefit plans	8.2	8.3	18.0	13.4
Postretirement Health Coverage | Salaried VEBA
Defined Benefit Plan Disclosure [Line Items]
Total net periodic postretirement benefit cost	1.0	0.5	1.9	1.1
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Total net periodic postretirement benefit cost	$ 1.3	$ 1.5	$ 2.7	$ 1.5