EARNINGS ATTRIBUTABLE TO ECOLAB PER COMMON SHARE ("EPS") (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Computations of the basic and diluted earnings attributable to Ecolab per share amounts
Net income attributable to Ecolab	$ 171.9	$ 193.6
Weighted-average common shares outstanding
Basic (in shares)	286.2	286.0
Effect of dilutive stock options and units (in shares)	1.9	2.8
Diluted (in shares)	288.1	288.8
Earnings attributable to Ecolab per common share
Basic EPS (in dollars per share)	$ 0.60	$ 0.68
Diluted EPS (in dollars per share)	$ 0.60	$ 0.67
Anti-dilutive securities excluded from the computation of diluted EPS	2.6	1.1