Fair Value Measurements - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - Commodity Contract - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Natural Gas | Basis Swaps
Financial Assets:
Assets, fair value disclosure	$ 1	$ 1
Natural Gas | Basis Swaps | Quoted Prices in Active Markets (Level 1)
Financial Assets:
Assets, fair value disclosure	0	0
Natural Gas | Basis Swaps | Significant Other Observable Inputs (Level 2)
Financial Assets:
Assets, fair value disclosure	1	1
Natural Gas | Basis Swaps | Significant Unobservable Inputs (Level 3)
Financial Assets:
Assets, fair value disclosure	0	0
Natural Gas | Price Swaps
Financial Liabilities:
Liabilities, fair value disclosure	86	117
Natural Gas | Price Swaps | Quoted Prices in Active Markets (Level 1)
Financial Liabilities:
Liabilities, fair value disclosure	0	0
Natural Gas | Price Swaps | Significant Other Observable Inputs (Level 2)
Financial Liabilities:
Liabilities, fair value disclosure	86	117
Natural Gas | Price Swaps | Significant Unobservable Inputs (Level 3)
Financial Liabilities:
Liabilities, fair value disclosure	0	0
Brent Crude Oil (Brent) Linked Gas Sales Contract
Financial Assets:
Assets, fair value disclosure	56	110
Brent Crude Oil (Brent) Linked Gas Sales Contract | Quoted Prices in Active Markets (Level 1)
Financial Assets:
Assets, fair value disclosure	0	0
Brent Crude Oil (Brent) Linked Gas Sales Contract | Significant Other Observable Inputs (Level 2)
Financial Assets:
Assets, fair value disclosure	0	0
Brent Crude Oil (Brent) Linked Gas Sales Contract | Significant Unobservable Inputs (Level 3)
Financial Assets:
Assets, fair value disclosure	$ 56	$ 110