Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ / shares in Units, $ in Millions			6 Months Ended
	Jan. 27, 2025	Jan. 17, 2025	Jun. 30, 2025	Dec. 31, 2024
Franklin Mountain Energy
Consideration:
Coterra common stock issued in exchange for FME equity interests (in shares)	28,190,682
Coterra common stock closing price on January 27, 2025 (in dollar per share)	$ 27.83
Total value of Coterra common stock issued	$ 785
Cash consideration	1,733
Total consideration	2,518
Assets acquired:
Current assets	178
Proved oil and gas properties	1,833
Unproved oil and gas properties	590
Gathering and pipeline systems	172
Other assets	6
Total assets acquired	2,779
Liabilities assumed:
Current liabilities	239
Asset retirement obligations	13
Other liabilities	9
Total liabilities assumed	261
Net assets acquired	$ 2,518
Restricted cash				$ 107
Consideration transferred, cash			$ 16
Avant
Consideration:
Cash consideration		$ 1,518
Total consideration		1,518
Assets acquired:
Current assets		34
Proved oil and gas properties		640
Unproved oil and gas properties		696
Gathering and pipeline systems		161
Other assets		1
Total assets acquired		1,532
Liabilities assumed:
Current liabilities		3
Asset retirement obligations		6
Other liabilities		5
Total liabilities assumed		14
Net assets acquired		$ 1,518
Restricted cash				$ 109