CONSOLIDATED STATEMENT OF EQUITY - USD ($) shares in Millions, $ in Millions	Ecolab Shareholders Equity	Common Stock	Additional Paid-in Capital	Retained Earnings	OCI (Loss)	Treasury Stock	Non-Controlling Interest	Total
Balance at Dec. 31, 2017	$ 7,583.6	$ 354.7	$ 5,435.7	$ 8,011.6	$ (1,643.4)	$ (4,575.0)	$ 70.2	$ 7,653.8
Increase (Decrease) in Stockholders' Equity
New accounting guidance adoption	(43.6)			(43.6)				(43.6)
Net income	247.3			247.3			0.9	248.2
Comprehensive income (loss) activity	85.1				85.1		2.5	87.6
Cash dividends declared	(118.3)			(118.3)			(4.7)	(123.0)
Stock options and awards	62.0	0.8	60.8			0.4		62.0
Reacquired shares	(215.1)					(215.1)		(215.1)
Balance at Mar. 31, 2018	7,601.0	355.5	5,496.5	8,097.0	(1,558.3)	(4,789.7)	68.9	7,669.9
Balance at Dec. 31, 2017	7,583.6	354.7	5,435.7	8,011.6	(1,643.4)	(4,575.0)	70.2	7,653.8
Balance at Dec. 31, 2018	8,003.2	357.0	5,633.2	8,909.5	(1,761.7)	(5,134.8)	50.4	$ 8,053.6
Balance (in shares) at Dec. 31, 2018								287.7
Increase (Decrease) in Stockholders' Equity
New accounting guidance adoption	(2.8)			58.4	(61.2)			$ (2.8)
Net income	296.5			296.5			3.9	300.4
Comprehensive income (loss) activity	88.0				88.0		0.9	88.9
Cash dividends declared	(132.6)			(132.6)			(9.0)	(141.6)
Stock options and awards	99.8	1.2	97.8			0.8		99.8
Reacquired shares	(131.4)					(131.4)		(131.4)
Balance at Mar. 31, 2019	$ 8,220.7	$ 358.2	$ 5,731.0	$ 9,131.8	$ (1,734.9)	$ (5,265.4)	$ 46.2	$ 8,266.9
Balance (in shares) at Mar. 31, 2019								288.2