Retirement Benefits (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]          
Settlement loss $ 12.6 $ 0 $ 12.6 $ 0  
Company contributions     95.4 43.9 78.2
Business Realignment and Reorganization [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Special termination benefits 3.0   5.7    
Curtailment losses 3.1   3.1    
Minimum [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Total expected contributions for current fiscal year     130    
Maximum [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Total expected contributions for current fiscal year     $ 150