Employee Benefit Obligations - Summary of Pension Plan Assets as of Measurement Date (Details)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocation, target	100.00%
Pension plan asset allocations	100.00%	100.00%
Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	27.00%	52.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	28.00%	19.00%
Other plan asset investments
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocations	45.00%	29.00%
Minimum | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocation, target	0.00%
Minimum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocation, target	0.00%
Minimum | Other plan asset investments
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocation, target	0.00%
Maximum | Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocation, target	60.00%
Maximum | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocation, target	40.00%
Maximum | Other plan asset investments
Defined Benefit Plan Disclosure [Line Items]
Pension plan asset allocation, target	100.00%