Annual report pursuant to Section 13 and 15(d)

Retirement Benefits (Details)

v3.8.0.1
Retirement Benefits (Details)
$ in Millions
 1 Months Ended 12 Months Ended
Sep. 30, 2016
USD ($)
Sep. 30, 2017
USD ($)
program
shares
Sep. 30, 2016
USD ($)
Sep. 30, 2015
USD ($)
Retirement and Postemployment Benefits        
Percentage of employee participation in the defined benefit retirement programs   44.00%    
Number of defined benefit retirement programs in which a specified percentage of employees participate | program   1    
Number of defined benefit retirement programs | program   4    
Pension Expense   $ 0.0 $ 0.0 $ 17.7
Amounts recorded in the consolidated balance sheets:        
Accrued pension costs, long-term portion $ 232.7 $ 129.6 232.7  
Plan Assets        
Reporting entity's common stock owned by trust (in shares) | shares   0    
Pension Plans Defined Benefit        
Accumulated other comprehensive loss        
Net actuarial gains (losses) 103.4 $ (71.9) 103.4  
Prior service cost (1.6) 1.0 (1.6)  
Aggregate tax effect (35.2) (25.0) (35.2)  
Amount that will be amortized from accumulated other comprehensive loss into net benefit costs   4.1    
Accumulated Benefit Obligation        
Accumulated benefit obligation 414.7 407.7 414.7  
U.S. Pension Benefits        
Retirement and Postemployment Benefits        
Decrease in projected obligation 81.9      
Defined benefit plans        
Service cost   3.6 3.9 4.3
Interest cost   8.8 9.5 14.4
Expected return on plan assets   (13.7) (9.7) (14.3)
Amortization of unrecognized prior service cost, net   0.4 0.6 0.9
Amortization of actuarial loss   3.6 3.8 5.3
Settlement expense 17.7 0.1 0.0 17.7
Net pension costs   2.8 8.1 28.3
Change in benefit obligation:        
Projected benefit obligation at beginning of year   294.2 272.2  
Service cost   3.6 3.9 4.3
Interest cost   8.8 9.5 14.4
Actuarial loss (gain)   (6.9) 19.7  
Benefits paid (75.9) (11.0) (11.1)  
Gain due to settlement   (6.9) 0.0  
Employee contributions   0.0 0.0  
Effect of exchange rates on projected benefit obligation   0.0 0.0  
Projected benefit obligation at end of year 294.2 281.8 294.2 272.2
Change in plan assets:        
Fair value of plan assets at beginning of year   173.7 158.9  
Actual return on plan assets   17.9 19.1  
Employee and employer contributions   81.8 6.8  
Benefits paid (75.9) (11.0) (11.1)  
Effect of exchange rates on plan assets   0.0 0.0  
Fair value of plan assets at end of year 173.7 262.4 173.7 $ 158.9
Funded status:        
Plan assets less than benefit obligations (120.5) (19.4) (120.5)  
Amounts recorded in the consolidated balance sheets:        
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent   8.2    
Accrued pension costs, current portion (1.8) (1.8) (1.8)  
Accrued pension costs, long-term portion 118.7 25.8 118.7  
Plan assets less than benefit obligations (120.5) (19.4) (120.5)  
Accumulated Benefit Obligation        
Projected benefit obligation 294.2 27.7 294.2  
Accumulated benefit obligation 276.5 27.6 276.5  
Fair value of plan assets $ 173.7 $ 0.0 $ 173.7  
Actuarial Assumptions        
Discount rate for obligation, end of year (as a percent) 3.60% 3.70% 3.60% 4.40%
Discount rate for expense, during the year (as a percent)   3.50% 4.40% 4.40%
Expected rate of return on plan assets (as a percent)   5.60% 5.50% 6.30%
Rate of compensation increase (as a percent)   3.00% 3.00% 3.00%
Plan Assets        
Maximum target investment in return seeking investments as a percentage of total domestic plan assets   60.00%    
Maximum equity investment in one entity as a percent of total equity portfolio   10.00%    
U.S. Pension Benefits | Accumulated Other Comprehensive Income        
Defined benefit plans        
Settlement expense $ (6.0)      
Non-U.S. Pension Plans        
Defined benefit plans        
Service cost   $ 1.3 $ 1.8 $ 1.7
Interest cost   0.7 1.8 2.8
Expected return on plan assets   (0.5) (1.0) (1.0)
Amortization of unrecognized prior service cost, net   0.1 0.1 0.0
Amortization of actuarial loss   1.1 0.3 0.1
Settlement expense   0.6 0.5 0.0
Net pension costs   3.3 3.5 3.6
Change in benefit obligation:        
Projected benefit obligation at beginning of year   140.9 134.2  
Service cost   1.3 1.8 1.7
Interest cost   0.7 1.8 2.8
Actuarial loss (gain)   (9.5) 11.7  
Benefits paid   (5.7) (8.8)  
Gain due to settlement   (1.2) 0.0  
Employee contributions   0.8 0.7  
Effect of exchange rates on projected benefit obligation   6.1 (0.5)  
Projected benefit obligation at end of year 140.9 133.4 140.9 134.2
Change in plan assets:        
Fair value of plan assets at beginning of year   29.7 29.5  
Actual return on plan assets   0.3 0.5  
Employee and employer contributions   8.5 8.5  
Benefits paid   (5.7) (8.8)  
Effect of exchange rates on plan assets   0.2 0.0  
Fair value of plan assets at end of year 29.7 31.4 29.7 $ 29.5
Funded status:        
Plan assets less than benefit obligations (111.2) (102.0) (111.2)  
Amounts recorded in the consolidated balance sheets:        
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent   0.4    
Accrued pension costs, current portion (6.6) (6.8) (6.6)  
Accrued pension costs, long-term portion 104.6 95.6 104.6  
Plan assets less than benefit obligations (111.2) (102.0) (111.2)  
Accumulated Benefit Obligation        
Projected benefit obligation 108.6 102.0 108.6  
Accumulated benefit obligation 108.6 102.0 108.6  
Fair value of plan assets $ 0.0 $ 0.0 $ 0.0  
Actuarial Assumptions        
Discount rate for obligation, end of year (as a percent) 1.00% 1.10% 1.00% 2.10%
Discount rate for expense, during the year (as a percent)   0.50% 1.70% 1.90%
Expected rate of return on plan assets (as a percent)   2.00% 2.00% 3.50%
Rate of compensation increase (as a percent)   2.00% 2.00% 0.20%
Other Postretirement Benefit Plan [Member]        
Defined benefit plans        
Service cost   $ 0.4 $ 0.4  
Interest cost   0.2 0.3  
Change in benefit obligation:        
Projected benefit obligation at beginning of year   10.3 10.3  
Service cost   0.4 0.4  
Interest cost   0.2 0.3  
Actuarial loss (gain)   0.9 (0.2)  
Benefits paid   (1.0) (0.9)  
Projected benefit obligation at end of year $ 10.3 9.0 10.3 $ 10.3
Change in plan assets:        
Benefits paid   (1.0) (0.9)  
Amounts recorded in the consolidated balance sheets:        
Accrued pension costs, current portion (0.9) (0.8) (0.9)  
Accrued pension costs, long-term portion 9.4 8.2 9.4  
Accumulated other comprehensive loss        
Net actuarial gains (losses) 3.1 3.4 3.1  
Prior service cost 0.5 0.8 0.5  
Aggregate tax effect $ 1.3 1.6 $ 1.3  
Amount that will be amortized from accumulated other comprehensive loss into net benefit costs   $ 0.4    
Actuarial Assumptions        
Discount rate for obligation, end of year (as a percent) 3.10% 3.30% 3.10% 3.70%
Change in Accounting Method Accounted for as Change in Estimate [Member]        
Retirement and Postemployment Benefits        
Pension Expense   $ 3.1