Other Investments (Investment in Unconsolidated Entity) (Details) - Mountain Valley Pipeline LLC (Unconsolidated Entity) [Member] - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019
Income Statement
AFUDC	$ 120,874,005	$ 78,261,970	$ 348,654,366	$ 199,400,095
Other Income (Expense), net	(18,925)	1,771,678	680,682	5,055,405
Net Income	120,855,080	$ 80,033,648	349,335,048	$ 204,455,500
Assets:
Current Assets	265,509,949		265,509,949		$ 485,323,892
Construction Work in Progress	5,322,878,940		5,322,878,940		4,675,267,389
Other Assets	4,597,441		4,597,441		13,190,816
Total Assets	5,592,986,330		5,592,986,330		5,173,782,097
Liabilities and Equity:
Current Liabilities	197,319,584		197,319,584		466,776,233
Noncurrent Liabilities	315,000		315,000		0
Capital	5,395,351,746		5,395,351,746		4,707,005,864
Total Liabilities and Equity	$ 5,592,986,330		$ 5,592,986,330		$ 5,173,782,097