Pension and Postretirement Benefits - Narrative (Details) - USD ($) $ in Millions	1 Months Ended			12 Months Ended
	Mar. 31, 2019	Feb. 07, 2019	Jan. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 08, 2019
Defined Benefit Plan Disclosure [Line Items]
Pension settlement payments		$ 190.5		$ 0.0	$ 105.9	$ 0.0
Actuarial loss due to change in discount rate		53.0		167.0	151.0
Actuarial gain from updates to assumed cash balance conversion interest rates and cash balance interest crediting rate		10.0		12.0	19.0
Actuarial gain due to change in mortality assumptions				11.0	43.0
Actuarial loss due to change in assumed benefit commencement rates for terminated vested participants					17.0
Actuarial loss due to assumption changes in control provision		22.0
Underfunded of unfunded accumulated benefit obligations				280.1	197.9
Pension settlement charge		(85.8)		$ (0.6)	$ 0.0	0.0
Recognition period of short-term fluctuations in fair value for market-related valuation of assets				5 years
Target Asset Allocations (as a percent)				100.00%	100.00%
Maximum contributions per employee (as a percent)				50.00%
Employer matching contribution (as a percent)				50.00%
Employer matching contribution as a percent of employees' gross pay (as a percent)				7.00%
Net periodic benefit cost (credit)		1.2		$ 10.6	$ 9.4	$ 11.0
Executive
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation for former executives				6.9	6.1
Long-Term Pension and Postretirement Benefits [Member] | Executive
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation for former executives				$ 6.3	$ 5.9
Return-Seeking assets
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				56.00%	56.00%
Return-Seeking assets | Minimum
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				50.00%
Return-Seeking assets | Maximum
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				70.00%
Return-Seeking assets | Weighted Average
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				61.00%
Liability-Hedging assets
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				44.00%	44.00%
Liability-Hedging assets | Minimum
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				30.00%
Liability-Hedging assets | Maximum
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				50.00%
Liability-Hedging assets | Weighted Average
Defined Benefit Plan Disclosure [Line Items]
Target Asset Allocations (as a percent)				39.00%
United States | Minimum
Defined Benefit Plan Disclosure [Line Items]
Amortization period				6 years
United States | Maximum
Defined Benefit Plan Disclosure [Line Items]
Amortization period				21 years
Foreign Plan | Minimum
Defined Benefit Plan Disclosure [Line Items]
Amortization period				6 years
Foreign Plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Amortization period				31 years
Qualified Plan | Minimum
Defined Benefit Plan Disclosure [Line Items]
Proportion of compensation allocated to retirement plans annually (as a percent)				3.00%
Qualified Plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Proportion of compensation allocated to retirement plans annually (as a percent)				12.50%
Qualified Plan | United States
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term return on plan assets (as a percent)				6.50%	7.00%	7.00%
Expected future benefit payments in 2021				$ 0.0
Employer contributions					$ 0.0
Qualified Plan | United States | Defined Benefit Plan, Unfunded Plan
Defined Benefit Plan Disclosure [Line Items]
Underfunded of unfunded accumulated benefit obligations				268.7	190.4
Qualified Plan | United States | Equity funds
Defined Benefit Plan Disclosure [Line Items]
Unfunded commitments				0.3
Qualified Plan | United States | Venture Capital Fund
Defined Benefit Plan Disclosure [Line Items]
Unfunded commitments				19.9	0.9
Qualified Plan | Foreign Plan | Defined Benefit Plan, Unfunded Plan
Defined Benefit Plan Disclosure [Line Items]
Underfunded of unfunded accumulated benefit obligations				11.4	7.5
Non-Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Pension settlement payments	$ 105.9		$ 190.5
Non-Qualified Plan | United States
Defined Benefit Plan Disclosure [Line Items]
Pension settlement charge		85.8		0.6		$ 0.4
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Aggregate actuarial losses and prior service credit				164.7	24.3		$ 0.0
Actuarial loss		$ 80.5		$ 162.5	$ 111.2
Weighted average expected long-term return on plan assets (as a percent)		6.56%		6.19%	6.72%	6.72%
Expected future benefit payments in 2021				$ 96.0
Employer contributions		$ 191.0		5.1	$ 113.5
Net periodic benefit cost (credit)		0.5		(43.8)	(34.6)	$ 7.2
Pension Plans | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions in 2021				2.3
Postretirement Benefit Obligations
Defined Benefit Plan Disclosure [Line Items]
Aggregate actuarial losses and prior service credit				(2.4)	(3.3)
Actuarial loss		0.4		0.3	(0.1)
Expected future benefit payments in 2021				0.3
Employer contributions		0.1		0.7	0.6
Net periodic benefit cost (credit)		$ (0.2)		(0.4)	$ 0.1	$ (1.0)
Postretirement Benefit Obligations | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions in 2021				$ 0.3