Accumulated Other Comprehensive Loss (Reclassification) (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
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income (Loss) [Line Items]        
Other income/expense, net $ (4.7) $ (17.0) $ (13.0) $ (37.4)
Interest expense 23.4 31.5 52.5 64.8
Net Income Attributable to Air Products (290.0) (283.5) (614.6) (573.7)
Income (Loss) from discontinued operations, net of tax 0 0 0 3.1
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | (Gain) Loss on Cash Flow Hedges [Member]        
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income (Loss) [Line Items]        
Sales/Cost of sales 0.9 0.8 0.3 1.0
Other income/expense, net 16.0 (11.1) 30.1 (23.0)
Interest expense 0.7 (0.5) 0.7 (0.7)
Net Income Attributable to Air Products 17.6 (10.8) 31.1 (22.7)
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Pension and postretirement benefits [Member]        
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income (Loss) [Line Items]        
Net Income Attributable to Air Products $ 28.6 [1] $ 20.6 [1] $ 49.5 [1] $ 40.6 [1]
[1]
The components include items such as prior service cost amortization, actuarial loss amortization, and settlements and are reflected in net periodic benefit cost. Refer to Note 10, Retirement Benefits.