Retirement Plan And Other Post-Retirement Benefits (Schedule Of Health Care Cost Trend Rates) (Details)		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]
Rate of Medical Increase for Pre Age 65 Participants	[1]	6.93%	7.10%	7.28%
Rate of Medical Increase for Post Age 65 Participants	[1]	6.68%	6.73%	6.78%
Annual Rate of Increase in the Per Capita Cost of Covered Prescription Drug Benefits	[1]	7.17%	7.47%	7.78%
Annual Rate of Increase in the Per Capita Medicare Part B Reimbursement	[1]	6.68%	6.73%	6.78%
Annual Rate of Increase in the Per Capita Medicare Part D Subsidy	[1]	6.65%	6.79%	7.03%
Ultimate health care trend rate by 2028		4.50%

[1] It was assumed that this rate would gradually decline to 4.5% by 2028.