Cover page - shares	9 Months Ended
	Sep. 30, 2025	Oct. 22, 2025
Cover [Abstract]
Document Type	10-Q/A
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2025
Document Transition Report	false
Entity File Number	001-31539
Entity Registrant Name	SM ENERGY CO
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	41-0518430
Entity Address, Address Line One	1700 Lincoln Street
Entity Address, Address Line Two	Suite 3200
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80203
City Area Code	(303)
Local Phone Number	861-8140
Title of 12(b) Security	Common stock, $0.01 par value
Trading Symbol	SM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		114,554,192
Entity Central Index Key	0000893538
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q3
Amendment Flag	true
Amendment Description	The sole purpose of this Amendment No. 1 to our Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, originally filed with the Securities and Exchange Commission (the "SEC") on November 3, 2025 (the “Original Filing”), is to correct a typographical error in Part II, Item 1.A Risk Factors related to the Termination Fee under the Merger Agreement.