Annual report pursuant to Section 13 and 15(d)

Retirement Benefits (Details 3)

v2.4.0.6
Retirement Benefits (Details 3) (Postretirement healthcare plan, USD $)
In Millions, unless otherwise specified
12 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2010
Postretirement healthcare plan
     
Defined Benefit Retirement Plans      
Postretirement healthcare benefit cost $ 1.0 $ 1.3 $ 1.2
Weighted average assumptions used in revaluing obligation under the postretirement healthcare plan      
Discount rate for obligation, end of year (as a percent) 3.40% 4.10% 4.50%
Healthcare cost rate assumed for next year (as a percent) 7.85% 7.75% 7.75%
Ultimate trend rate (as a percent) 5.00% 5.00% 5.00%
One-percentage-point increase/decrease in the assumed healthcare cost trend rates      
Impact of a one percentage point increase in healthcare cost trends on service and interest costs 0.1    
Impact of a one percentage point decrease in healthcare cost trends on service and interest costs 0.1    
Impact of a one percentage point increase in healthcare cost trends on the benefit obligation 1.0    
Impact of a one percentage point decrease in healthcare cost trends on the benefit obligation 1.0    
Employer's expected annual future contribution to the postretirement healthcare plan $ 0.8