Other Retirement Plans (Tables)

9 Months Ended

Sep. 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 September 30:
2021	5,116	6,979	$	36.9	$	11.7	$	48.6
2020	1,452	1,469	$	7.2	$	1.7	$	8.9
For the Nine Months Ended September 30:
2021	2,412	6,979	$	81.1	$	21.9	$	103.0
2020	1,119	1,469	$	19.5	$	5.5	$	25.0