Pension, Health Care and Other Postretirement Benefits - Summary of the Obligation and the Assumptions Used for Postretirement Benefits Other than Pensions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Liabilities recognized in the Consolidated Balance Sheets:
Other accruals	$ (1,005.8)	$ (1,127.9)	$ (1,001.1)
Postretirement benefits other than pensions	(259.4)	(275.6)	(263.0)
Postretirement Benefits Other than Pensions
Benefit obligation:
Balances at beginning of year	291.6	280.5	274.6
Service cost	1.4	1.5	1.5
Interest cost	4.9	7.6	11.2
Actuarial (gain) loss	(4.1)	19.7	12.8
Plan amendments	(2.2)	1.0
Benefits paid	(15.2)	(18.7)	(19.6)
Balances at end of year	276.4	291.6	280.5
Liabilities recognized in the Consolidated Balance Sheets:
Other accruals	(17.0)	(16.0)	(17.5)
Postretirement benefits other than pensions	(259.4)	(275.6)	(263.0)
Total liabilities recognized	(276.4)	(291.6)	(280.5)
Amounts recognized in AOCI:
Net actuarial losses	(54.0)	(62.8)	(45.1)
Prior service credit (cost)	1.6	(0.9)	1.1
Total amounts recognized	$ (52.4)	$ (63.7)	$ (44.0)
Weighted-average assumptions used to determine benefit obligation:
Discount rate	2.83%	2.49%	3.22%
Health care cost trend rate - pre-65	6.38%	6.06%	6.38%
Health care cost trend rate - post-65	5.13%	5.13%	5.25%
Prescription drug cost increases	8.25%	8.25%	9.00%
Employer Group Waiver Plan (EGWP) trend rate	8.25%	8.25%	9.00%
Weighted-average assumptions used to determine net periodic benefit cost:
Discount rate	2.49%	3.22%	4.21%
Health care cost trend rate - pre-65	6.06%	6.38%	6.69%
Health care cost trend rate - post-65	5.13%	5.25%	4.94%
Prescription drug cost increases	8.25%	9.00%	9.75%