Accumulated Other Comprehensive Loss (Rollforward) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 6 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance $ (1,470.6)   $ (1,241.9)  
Other comprehensive income (loss) before reclassifications (237.1)   (505.3)  
Amounts reclassified from AOCL 46.2   80.6  
Net current period other comprehensive income (loss) (190.9) (71.2) (424.7) (18.6)
Amount attributable to noncontrolling interest 0.6 (3.5) (4.5) (4.6)
Ending Balance (1,662.1)   (1,662.1)  
Net loss on derivatives qualifying as hedges [Member]        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance (38.9)   (28.5)  
Other comprehensive income (loss) before reclassifications (0.4)   (24.2)  
Amounts reclassified from AOCL 17.6   31.1  
Net current period other comprehensive income (loss) 17.2   6.9  
Amount attributable to noncontrolling interest 0   0.1  
Ending Balance (21.7)   (21.7)  
Foreign currency translation adjustments [Member]        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance (507.9)   (268.7)  
Other comprehensive income (loss) before reclassifications (232.1)   (476.5)  
Amounts reclassified from AOCL 0   0  
Net current period other comprehensive income (loss) (232.1)   (476.5)  
Amount attributable to noncontrolling interest 0.6   (4.6)  
Ending Balance (740.6)   (740.6)  
Pension and postretirement benefits [Member]        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning balance (923.8)   (944.7)  
Other comprehensive income (loss) before reclassifications (4.6)   (4.6)  
Amounts reclassified from AOCL 28.6   49.5  
Net current period other comprehensive income (loss) 24.0   44.9  
Amount attributable to noncontrolling interest 0   0  
Ending Balance $ (899.8)   $ (899.8)