Summary Of Significant Accounting Policies (Schedule Of Depreciable Plant By Segment) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Depreciable plant	$ 12,233,508	$ 12,547,784
Exploration And Production [Member]
Segment Reporting Information [Line Items]
Depreciable plant	6,088,476	6,827,122
Pipeline And Storage [Member]
Segment Reporting Information [Line Items]
Depreciable plant	2,747,948	2,467,891
Gathering [Member]
Segment Reporting Information [Line Items]
Depreciable plant	971,665	932,583
Utility [Member]
Segment Reporting Information [Line Items]
Depreciable plant	2,411,707	2,306,603
All Other And Corporate [Member]
Segment Reporting Information [Line Items]
Depreciable plant	$ 13,712	$ 13,585