Income Taxes (Significant Components Of Deferred Tax Liabilities And Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Sep. 30, 2015
Deferred Tax Liabilities [Abstract]
Property, Plant and Equipment	$ 1,049,100	$ 1,291,718
Pension and Other Post-Retirement Benefit Costs	151,903	141,032
Unrealized Hedging Gains	50,179	118,522
Other	55,457	51,230
Total Deferred Tax Liabilities	1,306,639	1,602,502
Deferred Tax Assets [Abstract]
Pension and Other Post-Retirement Benefit Costs	(195,829)	(168,451)
Tax Loss and Credit Carryforwards	(194,875)	(185,681)
Other	(92,140)	(110,408)
Total Deferred Tax Assets	(482,844)	(464,540)
Total Net Deferred Income Taxes	$ 823,795	$ 1,137,962