Annual report pursuant to Section 13 and 15(d)

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

v3.10.0.1
Retirement Benefits - Pension Plans and Defined Contribution Plans (Details) - USD ($)
$ in Millions
12 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2016
Cash Flows      
Cash contribution to defined benefit retirement plans $ 10.9 $ 90.6 $ 15.5
Defined Contribution Plans      
Employer's contribution to defined contribution plans (as a percent) 4.00%    
Expenses related to defined contribution plans $ 11.3 11.4 9.9
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 [Member]      
Fair Value Measurements      
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) $ (0.9) (0.9)  
Other Postretirement Benefits Cost (Reversal of Cost) 0.1 0.3 0.3
Cash Flows      
Estimated cash contribution to defined benefit retirement plans 0.8    
Pension Plans Defined Benefit      
Cash Flows      
Cash contribution to defined benefit retirement plans 10.0 $ 89.6 $ 14.6
Pension Plans Defined Benefit | Minimum      
Cash Flows      
Estimated cash contribution to defined benefit retirement plans $ 10.0    
Domestic Plan [Member]      
Fair Value Measurements      
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate 3.40% 3.50% 4.40%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) $ 14.7 $ 6.9  
Employee and employer contributions $ 1.8 $ 81.8  
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase 3.00% 3.00% 3.00%
Fair value of plan assets $ 253.3 $ 262.4 $ 173.7
Estimated Future Benefit Payments      
2017 14.0    
2018 14.3    
2019 15.0    
2020 15.5    
2021 16.0    
2023 - 2027 $ 83.8    
Foreign Plan [Member]      
Fair Value Measurements      
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate 1.50% 0.50% 1.70%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) $ (0.4) $ 9.5  
Employee and employer contributions $ 9.0 $ 8.5  
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 $ 31.9 $ 31.4 $ 29.7
Estimated Future Benefit Payments      
2017 7.7    
2018 7.9    
2019 7.2    
2020 7.3    
2021 7.3    
2023 - 2027 33.6    
Foreign Plan [Member] | Cash equivalents | Level 1      
Fair Value Measurements      
Fair value of plan assets 2.4 5.2  
Foreign Plan [Member] | Cash equivalents | Level 2      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Cash equivalents | Level 3      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member]      
Fair Value Measurements      
Fair value of plan assets 31.9 31.4  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Level 1      
Fair Value Measurements      
Fair value of plan assets 27.4 27.5  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Level 2      
Fair Value Measurements      
Fair value of plan assets 2.1 1.9  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Level 3      
Fair Value Measurements      
Fair value of plan assets 2.4 2.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Cash equivalents      
Fair Value Measurements      
Fair value of plan assets 2.4 5.2  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Equity securities      
Fair Value Measurements      
Fair value of plan assets 7.3 6.8  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Equity securities | Level 1      
Fair Value Measurements      
Fair value of plan assets 7.3 6.8  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Equity securities | Level 2      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Equity securities | Level 3      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Government index funds      
Fair Value Measurements      
Fair value of plan assets 5.6 5.7  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Government index funds | Level 1      
Fair Value Measurements      
Fair value of plan assets 5.6 5.7  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Government index funds | Level 2      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Government index funds | Level 3      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Corporate bond funds      
Fair Value Measurements      
Fair value of plan assets 12.1 9.8  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Corporate bond funds | Level 1      
Fair Value Measurements      
Fair value of plan assets 12.1 9.8  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Corporate bond funds | Level 2      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Corporate bond funds | Level 3      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Real estate and real estate funds      
Fair Value Measurements      
Fair value of plan assets 2.4 2.0  
Foreign Plan [Member] | 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  
Foreign Plan [Member] | 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  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Real estate and real estate funds | Level 3      
Fair Value Measurements      
Fair value of plan assets 2.4 2.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Other      
Fair Value Measurements      
Fair value of plan assets 2.1 1.9  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Other | Level 1      
Fair Value Measurements      
Fair value of plan assets 0.0 0.0  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Other | Level 2      
Fair Value Measurements      
Fair value of plan assets 2.1 1.9  
Foreign Plan [Member] | Estimate of Fair Value Measurement [Member] | Other | Level 3      
Fair Value Measurements      
Fair value of plan assets $ 0.0 $ 0.0