Retirement Benefits (Details 4)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Equity Securities [Member]
Asset Allocation
Minimum	30.00%
Maximum	65.00%
Target Allocation	52.00%
As of the balance sheet date	52.00%	49.00%
Debt Securities [Member]
Asset Allocation
Minimum	35.00%
Maximum	50.00%
Target Allocation	40.00%
As of the balance sheet date	41.00%	43.00%
Other Security [Member]
Asset Allocation
Minimum	0.00%
Maximum	35.00%
Target Allocation	8.00%
As of the balance sheet date	7.00%	8.00%