Retirement Plans - Additional Information (Details) $ in Millions	1 Months Ended		12 Months Ended
	Oct. 31, 2019 USD ($) Letter	Sep. 30, 2019 USD ($)	Sep. 30, 2021	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Apr. 30, 2020 USD ($)	Feb. 29, 2020 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used, Minimum Outstanding Par Value of Bonds Used to Determine Future Discount Rate				$ 100.0
Defined benefit plan, accumulated benefit obligation		$ 6,438.9		6,682.2	$ 6,438.9
Defined benefit plan, effect of one percentage point increase on accumulated postretirement benefit obligation				10.0
Defined benefit plan, effect of one percentage point increase on service and interest cost components				1.0
Defined benefit plan, effect of one percentage point decrease on accumulated postretirement benefit obligation				8.0
Defined benefit plan, effect of one percentage point decrease on service and interest cost components				1.0
Multiemployer Plans, Withdrawal Obligation		237.2		$ 252.0	237.2
Periods of Payments Used to Calculate Withdrawal Liability in Connection with PIUMPF Withdrawal						20 years
Credit Adjusted Risk-Free Rate Used to Calculate Withdrawal Liability in Connection with PIUMPF Withdrawal						3.83%
Percentage of Employees Covered by Collective Bargaining Agreements				56.00%
Percentage of Employees Working Under Expired Collective Bargaining Agreement				15.00%
Percentage of Employees Covered By Collective Bargaining Agreements Expiring in One Year				21.00%
Defined Contribution Plan Employer Contribution on Basic Salary, Maximum, High End of Range				7.50%
Defined Contribution Plan Employer Contribution on Basic Salary, Automatic Matching Contribution				2.50%
Defined Contribution Plan Employer Contribution on Basic Salary, Employees Covered under a CBA, Maximum, Low End of Range				3.00%
Defined Contribution Plan Employer Contribution on Basic Salary, Employees Covered under a CBA, Maximum, High End of Range				4.00%
Defined Contribution Plan, Cost				$ 150.1	150.9	$ 113.7
Pace Industry Union Management Pension Fund [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plans, Withdrawal Obligation		$ 170.3			$ 170.3
Periods of Payments Used to Calculate Withdrawal Liability in Connection with PIUMPF Withdrawal		20 years
Withdrawal obligation, per month		$ 0.7
Withdrawal obligation accumulated funding deficiency								$ 51.2
Subsidiary [Member] | Pace Industry Union Management Pension Fund [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plans, Withdrawal Obligation	$ 2.3
Periods of Payments Used to Calculate Withdrawal Liability in Connection with PIUMPF Withdrawal	20 years
Number of additional demand letters | Letter	2
Withdrawal obligation accumulated funding deficiency	$ 2.0						$ 1.3
Pace Industry Union Management Pension Fund [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plans, Withdrawal Obligation						180.0
Central States Pension Fund [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multiemployer Plans, Withdrawal Obligation						$ 4.2
Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Adjustment to Pri-2012 mortality tables with specific gender and job classification				5.00%	6.00%
Adjustment to Rp2014 tables with specific gender and job classification						10.00%
Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Adjustment to Pri-2012 mortality tables with specific gender and job classification				12.00%	12.00%
Adjustment to Rp2014 tables with specific gender and job classification						14.00%
Defined Contribution Plan Employer Contribution on Basic Salary, Matching Contribution				5.00%
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year				$ 23.0
Pension Plan [Member] | United States [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets				6.25%	6.50%	6.50%
Pension Plan [Member] | United States [Member] | Non-Qualified Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, plan with benefit obligation in excess of plan assets, benefit obligation				$ 222.3
Defined benefit plan, pension plan with accumulated benefit obligation in excess of plan assets, accumulated benefit obligation				222.2
Defined benefit plan, plan with benefit obligation in excess of plan assets, fair value of plan assets				$ 36.8
Pension Plan [Member] | United States [Member] | Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets			6.00%
Pension Plan [Member] | Foreign Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets				4.26%	4.69%	4.98%
Pension Plan [Member] | Foreign Plan [Member] | Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets			3.73%
Other Pension, Postretirement and Supplemental Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension and other postretirement plans, assets				$ 168.9
Pension and other postretirement plans, liabilities				$ 176.1