Other Retirement Plans (Tables)

6 Months Ended

Jun. 30, 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 June 30:
2021	2,532	6,979	$	21.7	$	8.0	$	29.7
2020	1,424	1,469	$	6.9	$	2.1	$	9.0
For the Six Months Ended June 30:
2021	2,412	6,979	$	44.2	$	10.2	$	54.4
2020	1,119	1,469	$	12.3	$	3.8	$	16.1