Supplemental Information on Natural Gas and Oil Exploration, Development and Production Activities (Unaudited) - Standardized Measure of Discounted Future Net Cash Flows (Parenthetical) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) MMcfe
Extractive Industries [Abstract]
Proved undeveloped reserves removed and deferred | MMcfe	1,300
Undiscounted future asset retirement costs estimation | $	$ 308.5