Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2023	Jan. 31, 2024	Jun. 30, 2023
Document and Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Document Transition Report	false
Entity File Number	1-9328
Entity Registrant Name	ECOLAB INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	41-0231510
Entity Address, Address Line One	1 Ecolab Place
Entity Address, City or Town	St. Paul
Entity Address, State or Province	MN
Entity Address, Postal Zip Code	55102
City Area Code	800
Local Phone Number	232-6522
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 53,175,318,295
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		285,513,155
Entity Central Index Key	0000031462
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false
Auditor Name	PricewaterhouseCoopers LLP
Auditor Firm ID	238
Auditor Location	Minneapolis, Minnesota
Document Financial Statement Error Correction [Flag]	false
COMMON STOCK
Document and Entity Information
Title of 12(b) Security	Common Stock, $1.00 par value
Trading Symbol	ECL
Security Exchange Name	NYSE
2.625% Euro Notes due 2025
Document and Entity Information
Title of 12(b) Security	2.625% Euro Notes due 2025
Trading Symbol	ECL 25
Security Exchange Name	NYSE