Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Apr. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Proceeds from sale of investment shares		$ 189,249	$ 0
Net carrying value of Convertible Notes		4,769,319		$ 5,591,072
Equitrans Midstream
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Proceeds from sale of investment shares	$ 189,000
Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Net carrying value of Convertible Notes		4,700,000		5,500,000
Senior Notes | Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Estimated fair value of long-term debt		5,200,000		6,500,000
Note payable to EQM | Note payable to EQM
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Net carrying value of Convertible Notes		95,728		99,838
Note payable to EQM | Significant unobservable inputs (Level 3) | Note payable to EQM
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Estimated fair value of long-term debt		$ 96,000		$ 118,000