Other Retirement Plans (Tables)

3 Months Ended

Mar. 31, 2021

Retirement Benefits [Abstract]

Schedule of Covered Employees and Contributions, Multiemployer Plans

Total contributions to multiemployer plans and the related number of employees covered by these plans for the periods indicated were as follows:

	Multiemployer Plans
	Covered Employees		Contributions (in millions)
	Low	High	Pension		Other Multiemployer		Total
For the Three Months Ended March 31:
2021	2,412	2,532	$	22.5	$	2.2	$	24.7
2020	1,119	1,424	$	5.4	$	1.7	$	7.1