Employee Retirement Plans and Postretirement Benefits - Net Periodic Pension (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 108.5	$ 139.3
Total other pension and postretirement (benefit) cost, net	(46.4)	(30.3)	$ (2.9)
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.7	2.7	4.0
Interest cost	93.9	120.5	161.9
Expected return on plan assets, net of expenses	(161.6)	(161.8)	(217.3)
Amortization of prior service (benefit) cost	0.4	0.3	1.1
Amortization of net actuarial (gain) loss	8.7	7.3	10.4
Curtailment, settlement or special termination benefit (gain) loss	5.4	0.0	30.5
Expected participant contributions	(0.4)	(0.4)	(0.7)
Total other pension and postretirement (benefit) cost, net	(53.6)	(34.1)	(14.1)
Net periodic pension and OPEB (benefit) cost	(50.9)	(31.4)	(10.1)
OPEB
Defined Benefit Plan Disclosure [Line Items]
Service cost	6.0	6.0	7.0
Interest cost	14.6	18.8	25.5
Expected return on plan assets, net of expenses	0.0	0.2	0.5
Amortization of prior service (benefit) cost	(0.7)	(0.7)	(0.7)
Amortization of net actuarial (gain) loss	(6.7)	(14.5)	(14.1)
Curtailment, settlement or special termination benefit (gain) loss	0.0	0.0	0.0
Expected participant contributions	0.0	0.0	0.0
Total other pension and postretirement (benefit) cost, net	7.2	3.8	11.2
Net periodic pension and OPEB (benefit) cost	13.2	9.8	18.2
Consolidated
Defined Benefit Plan Disclosure [Line Items]
Service cost	8.7	8.7	11.0
Interest cost	108.5	139.3	187.4
Expected return on plan assets, net of expenses	(161.6)	(161.6)	(216.8)
Amortization of prior service (benefit) cost	(0.3)	(0.4)	0.4
Amortization of net actuarial (gain) loss	2.0	(7.2)	(3.7)
Curtailment, settlement or special termination benefit (gain) loss	5.4	0.0	30.5
Expected participant contributions	(0.4)	(0.4)	(0.7)
Total other pension and postretirement (benefit) cost, net	(46.4)	(30.3)	(2.9)
Net periodic pension and OPEB (benefit) cost	$ (37.7)	$ (21.6)	$ 8.1