Cover - shares	3 Months Ended
	Mar. 31, 2024	Apr. 30, 2024
Cover [Abstract]
Document Type	10-Q/A
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-32269
Entity Registrant Name	EXTRA SPACE STORAGE INC.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	20-1076777
Entity Address, Address Line One	2795 East Cottonwood Parkway, Suite 300
Entity Address, City or Town	Salt Lake City
Entity Address, State or Province	UT
Entity Address, Postal Zip Code	84121
City Area Code	801
Local Phone Number	365-4600
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	EXR
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		211,725,246
Amendment Flag	true
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001289490
Current Fiscal Year End Date	--12-31
Amendment Description	This Amendment No. 1 on Form 10-Q/A (this “Amendment”) amends the Quarterly Report on Form 10-Q for the quarter ended March 31, 2024 originally filed by Extra Space Storage Inc., a Maryland corporation (“we,” “our,” “us” or the “Company”), with the Securities and Exchange Commission (“SEC”) on May 3, 2024 (the “Original Filing”). We are filing this Amendment solely to (a) amend Item 5 of Part II of the Original Filing to include information concerning a Rule 10b5-1 trading arrangement adopted by our Chief Executive Officer on March 1, 2024 that was inadvertently omitted from the Original Filing and (b) amend Item 6 of Part II of the Original Filing to include (i) new certifications of our Chief Executive Officer and Chief Financial Officer, as Exhibits 31.1 and 31.2, pursuant to Rule 13a-14(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Because no financial statements have been included in this Amendment and this Amendment does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4 and 5 of the certifications have been omitted. We are not furnishing new certifications under Section 906 of the Sarbanes-Oxley Act of 2002 because no financial statements are being filed with this Amendment. The complete text of Item 5 of Part II has been set forth in its entirety in accordance with Rule 12b-15 under the Exchange Act.Except as described above, no other changes have been made to the Original Filing. The Original Filing continues to speak as of the date of the Original Filing, and we have not updated the disclosures contained therein to reflect any events occurring subsequent to the filing of the Original Filing other than as expressly indicated in this Amendment. Accordingly, this Amendment should be read in conjunction with the Original Filing and our other filings made with the SEC subsequent to May 3, 2024, including any amendments to those filings.