Summary of Significant Accounting Policies and Other Matters - Investments (Details) - Mountain Valley Pipeline $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2016 mi	Dec. 31, 2025 USD ($)	Jun. 30, 2026 USD ($)	Feb. 01, 2026	Jan. 31, 2026	Dec. 31, 2024 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2019 USD ($)
Schedule of Equity Method Investments [Line Items]
Equity method investments		$ 530.0				$ 530.0
CET Gas
Schedule of Equity Method Investments [Line Items]
Number of miles in pipeline construction | mi	300
Equity method investments		168.0						$ 530.0
Aggregate project cost		8,100.0					$ 8,100.0
Payments to acquire equity method investments		530.0
Income (loss) from equity method investments		30.0
Income (loss) from equity method Investments, after tax		$ 21.0
CET Gas | Scenario, Forecast
Schedule of Equity Method Investments [Line Items]
Equity method investments			$ 357.5
CET Gas | Subsequent Event
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percent (in percent)				6.60%	40.00%
CET Gas | Mountain Valley Pipeline
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percent (in percent)	12.50%