Annual report pursuant to Section 13 and 15(d)

Retirement Benefits - Pension Plans and Defined Contribution Plans (Details)

v3.21.2
Retirement Benefits - Pension Plans and Defined Contribution Plans (Details) - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
Cash Flows          
Cash contribution to defined benefit retirement plans     $ 11.6 $ 12.4 $ 10.3
Defined Contribution Plans          
Employer's contribution to defined contribution plans (as a percent)     4.00%    
Expenses related to defined contribution plans     $ 15.7 15.3 11.6
Minimum          
Defined Contribution Plans          
Contribution vesting period     0 years    
Maximum          
Defined Contribution Plans          
Employer's matching contribution to defined contribution plans (as a percent)     6.00%    
Contribution vesting period     5 years    
Other Postretirement Benefits Plan          
Fair Value Measurements          
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)     $ 0.2 2.0  
Other Postretirement Benefits Cost (Reversal of Cost)     0.2 0.1 (0.1)
Cash Flows          
Estimated cash contribution to defined benefit retirement plans $ 0.8   0.8    
Pension Plans Defined Benefit          
Cash Flows          
Cash contribution to defined benefit retirement plans     11.0 $ 10.0 $ 9.3
Pension Plans Defined Benefit | Minimum          
Cash Flows          
Estimated cash contribution to defined benefit retirement plans 10.9   $ 10.9    
Domestic Plan          
Fair Value Measurements          
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate     3.90% 3.00% 4.10%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)     $ 5.5 $ (20.6)  
Employee and employer contributions     $ 1.9 $ 1.8  
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase     2.40% 3.00% 3.00%
Fair value of plan assets 303.2 $ 297.9 $ 303.2 $ 297.9 $ 280.6
Fair value of pension assets attributable to acquisitions     0.0 0.0  
Estimated Future Benefit Payments          
2017 16.1   16.1    
2018 16.2   16.2    
2019 16.5   16.5    
2020 16.7   16.7    
2021 16.9   16.9    
2027-2031 84.6   84.6    
Defined Contribution Plans          
Defined Benefit Plan, Benefit Obligation, Business Combination     $ 0.0 $ 0.0  
Foreign Plan          
Fair Value Measurements          
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate     0.70% 0.30% 1.50%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)     $ 7.0 $ (2.3)  
Employee and employer contributions     $ 10.1 $ 9.2  
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase     2.00% 2.00% 2.00%
Fair value of plan assets 47.6 43.8 $ 47.6 $ 43.8 $ 33.5
Fair value of pension assets attributable to acquisitions     0.0 7.6  
Estimated Future Benefit Payments          
2017   9.1   9.1  
2018   9.2   9.2  
2019   8.8   8.8  
2020   8.6   8.6  
2021   8.8   8.8  
2027-2031   41.1   41.1  
Defined Contribution Plans          
Defined Benefit Plan, Benefit Obligation, Business Combination     0.0 37.7  
Defined Benefit Plan, Plan Assets, Payment for Settlement 0.0 0.0 (4.1) (4.7)  
Foreign Plan | Cash equivalents | Level 1          
Fair Value Measurements          
Fair value of plan assets 4.8 5.6 4.8 5.6  
Foreign Plan | Cash equivalents | Level 2          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Cash equivalents | Level 3          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member]          
Fair Value Measurements          
Fair value of plan assets 47.6 43.8 47.6 43.8  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Level 1          
Fair Value Measurements          
Fair value of plan assets 39.6 36.7 39.6 36.7  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Level 2          
Fair Value Measurements          
Fair value of plan assets 3.5 3.3 3.5 3.3  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Level 3          
Fair Value Measurements          
Fair value of plan assets 4.5 3.8 4.5 3.8  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Cash equivalents          
Fair Value Measurements          
Fair value of plan assets 4.8 5.6 4.8 5.6  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Equity securities          
Fair Value Measurements          
Fair value of plan assets 16.3 12.4 16.3 12.4  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Equity securities | Level 1          
Fair Value Measurements          
Fair value of plan assets 16.3 12.4 16.3 12.4  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Equity securities | Level 2          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Equity securities | Level 3          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Government index funds          
Fair Value Measurements          
Fair value of plan assets 4.8 6.0 4.8 6.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Government index funds | Level 1          
Fair Value Measurements          
Fair value of plan assets 4.8 6.0 4.8 6.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Government index funds | Level 2          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Government index funds | Level 3          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Corporate bond funds          
Fair Value Measurements          
Fair value of plan assets 13.7 12.7 13.7 12.7  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Corporate bond funds | Level 1          
Fair Value Measurements          
Fair value of plan assets 13.7 12.7 13.7 12.7  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Corporate bond funds | Level 2          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Corporate bond funds | Level 3          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Real estate and real estate funds          
Fair Value Measurements          
Fair value of plan assets 4.5 3.8 4.5 3.8  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Real estate and real estate funds | Level 1          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Real estate and real estate funds | Level 2          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Real estate and real estate funds | Level 3          
Fair Value Measurements          
Fair value of plan assets 4.5 3.8 4.5 3.8  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Other          
Fair Value Measurements          
Fair value of plan assets 3.5 3.3 3.5 3.3  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Other | Level 1          
Fair Value Measurements          
Fair value of plan assets 0.0 0.0 0.0 0.0  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Other | Level 2          
Fair Value Measurements          
Fair value of plan assets 3.5 3.3 3.5 3.3  
Foreign Plan | Estimate of Fair Value Measurement [Member] | Other | Level 3          
Fair Value Measurements          
Fair value of plan assets $ 0.0 $ 0.0 $ 0.0 $ 0.0