Pension, Health Care and Postretirement Benefits Other Than Pensions - Summary of the Components of the Net Pension Costs and Cumulative Other Comprehensive Loss Related to the Defined Benefit Pension Plans (Details) - Defined Benefit Pension - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Domestic Defined Benefit Pension Plans
Net pension cost (credit):
Service cost	$ 3.5	$ 7.3	$ 21.7
Interest cost	4.8	32.2	31.1
Expected return on plan assets	(5.3)	(53.0)	(48.3)
Amortization of prior service cost	1.4	3.5	1.4
Amortization of actuarial losses			6.2
Ongoing pension cost (credit)	4.4	(10.0)	12.1
Settlement cost (credit)	32.4	37.6	(2.0)
Curtailment cost		0.8
Net pension cost	36.8	28.4	10.1
Other changes in plan assets and projected benefit obligation recognized in AOCI (before taxes):
Net actuarial (gains) losses arising during the year	(22.0)	29.9	(65.8)
Prior service cost arising during the year	3.1	4.6	0.8
Amortization of actuarial losses			(6.2)
Amortization of prior service cost	(1.4)	(3.5)	(1.4)
(Loss) gain recognized for settlement	(32.4)	(37.6)	2.0
Prior service cost recognized for curtailment		(0.8)
Loss arising from curtailment		(0.8)
Total recognized in AOCI	(52.7)	(8.2)	(70.6)
Total recognized in net pension cost and AOCI	(15.9)	20.2	(60.5)
Foreign Defined Benefit Pension Plans
Net pension cost (credit):
Service cost	5.9	8.2	7.0
Interest cost	9.4	9.5	8.2
Expected return on plan assets	(10.3)	(10.8)	(9.0)
Amortization of actuarial losses	1.0	1.5	1.8
Ongoing pension cost (credit)	6.0	8.4	8.0
Settlement cost (credit)	0.3	(0.4)	0.1
Net pension cost	6.3	8.0	8.1
Other changes in plan assets and projected benefit obligation recognized in AOCI (before taxes):
Net actuarial (gains) losses arising during the year	13.2	(5.1)	(14.0)
Amortization of actuarial losses	(1.0)	(1.5)	(1.8)
(Loss) gain recognized for settlement	(0.3)	0.4	(0.1)
Loss arising from curtailment	(0.7)
Exchange rate gain (loss) recognized during the year	1.0	(2.0)	4.2
Total recognized in AOCI	12.2	(8.2)	(11.7)
Total recognized in net pension cost and AOCI	$ 18.5	$ (0.2)	$ (3.6)

Pension, Health Care and Postretirement Benefits Other Than Pensions - Summary of the Components of the Net Pension Costs and Cumulative Other Comprehensive Loss Related to the Defined Benefit Pension Plans (Details) - Defined Benefit Pension - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Domestic Defined Benefit Pension Plans

Net pension cost (credit):

Service cost

$ 3.5

$ 7.3

$ 21.7

Interest cost

4.8