Segment Information - Schedule of Balance Sheet Information by Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023
Segment Reporting Information [Line Items]
Net property, plant and equipment	$ 20,319,481	$ 19,606,583
Total assets	23,684,243	22,516,968
Operating Segments | Distribution
Segment Reporting Information [Line Items]
Net property, plant and equipment	14,907,406	14,402,578
Total assets	22,874,926	21,716,467
Operating Segments | Pipeline and Storage
Segment Reporting Information [Line Items]
Net property, plant and equipment	5,412,075	5,204,005
Total assets	5,721,542	5,504,972
Eliminations
Segment Reporting Information [Line Items]
Net property, plant and equipment	0	0
Total assets	$ (4,912,225)	$ (4,704,471)