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Business Combinations - Additional Information (Details) - USD ($) $ in Millions			12 Months Ended
	Aug. 22, 2025	Jul. 27, 2025	Sep. 30, 2025
MoGas Pipeline [Member]
Asset Acquisition, Contingent Consideration [Line Items]
Payments to Acquire Businesses, Gross			$ 176.1
Tennessee Natural Gas [Member]
Asset Acquisition, Contingent Consideration [Line Items]
Payments to Acquire Businesses, Gross		$ 2,480.0
Tennessee Natural Gas [Member] \| Senior Unsecured Bridge Facility [Member]
Asset Acquisition, Contingent Consideration [Line Items]
Line of credit facility maximum borrowing capacity	$ 2,480.0
Maturity term	364 days
Tennessee Natural Gas [Member] \| Senior Unsecured Bridge Facility [Member] \| Bridge Term Loan [Member]
Asset Acquisition, Contingent Consideration [Line Items]
Line of credit facility maximum borrowing capacity	$ 1,880.0
Tennessee Natural Gas [Member] \| Senior Unsecured Bridge Facility [Member] \| Delayed Draw Term Loan (DDTL) [Member]
Asset Acquisition, Contingent Consideration [Line Items]
Line of credit facility maximum borrowing capacity	$ 600.0
Tennessee Natural Gas [Member] \| Secured Overnight Financing Rate (SOFR) [Member] \| Senior Unsecured Bridge Facility [Member]
Asset Acquisition, Contingent Consideration [Line Items]
Debt instrument basis spread on variable rate	1.375%
Tennessee Natural Gas [Member] \| Base Rate [Member] \| Senior Unsecured Bridge Facility [Member]
Asset Acquisition, Contingent Consideration [Line Items]
Debt instrument basis spread on variable rate	0.375%