Employee Retirement Plans (Details 4)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Pension Benefit [Member]
Pension Plan
Actual Pension Plan	100.00%	100.00%
Target Asset Allocation	100.00%
Pension Benefit [Member] | Total domestic equity investments
Pension Plan
Actual Pension Plan	57.50%	53.50%
Target Asset Allocation	52.50%
Permitted Range - Minimum	40.00%
Permitted Range - Maximum	65.00%
Pension Benefit [Member] | International index equity mutual funds
Pension Plan
Actual Pension Plan	11.10%	10.50%
Target Asset Allocation	12.50%
Permitted Range - Minimum	7.50%
Permitted Range - Maximum	17.50%
Pension Benefit [Member] | Equity Securities [Member]
Pension Plan
Actual Pension Plan	68.60%	64.00%
Target Asset Allocation	65.00%
Permitted Range - Minimum	60.00%
Permitted Range - Maximum	70.00%
Pension Benefit [Member] | Fixed Income Funds And Cash Equivalents [Member]
Pension Plan
Actual Pension Plan	31.40%	36.00%
Target Asset Allocation	35.00%
Permitted Range - Minimum	30.00%
Permitted Range - Maximum	40.00%
VEBA Trust [Member]
Pension Plan
Actual Pension Plan	100.00%	100.00%
Target Asset Allocation	100.00%
VEBA Trust [Member] | Total domestic equity investments
Pension Plan
Actual Pension Plan	65.60%	68.50%
Target Asset Allocation	65.00%
Permitted Range - Minimum	60.00%
Permitted Range - Maximum	70.00%
VEBA Trust [Member] | Fixed Income Funds And Cash Equivalents [Member]
Pension Plan
Actual Pension Plan	34.40%	31.50%
Target Asset Allocation	35.00%
Permitted Range - Minimum	30.00%
Permitted Range - Maximum	40.00%