Pension Benefits - Narrative (Details) $ in Millions			12 Months Ended
	Aug. 22, 2019 USD ($)	Jul. 13, 2018 USD ($)	Dec. 31, 2019 USD ($) employees	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Employer Contributions	$ 55.3	$ 5.1
Unrecognized pension gain (loss) arising during the year			$ (4.8)	$ (8.0)	$ 3.9
Defined contribution plan, cost			$ 26.0	15.1	10.6
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Number of participants and beneficiaries | employees			8,650
Number of active employees | employees			1,250
Contribution as a percentage of compensation			3.00%
Actuarial loss amortization period			22 years
Amounts that will be amortized from AOCI in next fiscal Year			$ 5.9
Employer Contributions			55.3	5.1
Unfunded liability			(4.1)	55.2
Pension expense			(5.4)	(4.3)	(7.7)
Unrecognized pension gain (loss) arising during the year			(4.2)	(11.5)	4.9
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Unfunded liability			28.9	24.2
Pension expense			1.0	0.8	0.8
Unrecognized pension gain (loss) arising during the year			$ (5.6)	$ 1.3	$ (1.6)