CONSOLIDATED STATEMENT OF EQUITY - USD ($) $ 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	598.6			598.6			3.2	601.8
Comprehensive income (loss) activity	50.7				50.7		1.0	51.7
Cash dividends declared	(236.7)			(236.7)			(15.4)	(252.1)
Stock options and awards	112.7	1.2	109.9			1.6		112.7
Reacquired shares	(215.8)					(215.8)		(215.8)
Balance at Jun. 30, 2018	7,849.5	355.9	5,545.6	8,329.9	(1,592.7)	(4,789.2)	59.0	7,908.5
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
Increase (Decrease) in Stockholders' Equity
Net income	351.3			351.3			2.3	353.6
Comprehensive income (loss) activity	(34.4)				(34.4)		(1.5)	(35.9)
Cash dividends declared	(118.4)			(118.4)			(10.7)	(129.1)
Stock options and awards	50.7	0.4	49.1			1.2		50.7
Reacquired shares	(0.7)					(0.7)		(0.7)
Balance at Jun. 30, 2018	7,849.5	355.9	5,545.6	8,329.9	(1,592.7)	(4,789.2)	59.0	7,908.5
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
Increase (Decrease) in Stockholders' Equity
New accounting guidance adoption	(2.8)			58.4	(61.2)			(2.8)
Net income	665.1			665.1			7.5	672.6
Comprehensive income (loss) activity	(13.5)				(13.5)		1.8	(11.7)
Cash dividends declared	(265.0)			(265.0)			(15.7)	(280.7)
Stock options and awards	185.9	1.9	182.5			1.5		185.9
Reacquired shares	(347.5)					(347.5)		(347.5)
Balance at Jun. 30, 2019	8,225.4	358.9	5,815.7	9,368.0	(1,836.4)	(5,480.8)	44.0	8,269.4
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
Increase (Decrease) in Stockholders' Equity
Net income	368.6			368.6			3.6	372.2
Comprehensive income (loss) activity	(101.5)				(101.5)		0.9	(100.6)
Cash dividends declared	(132.4)			(132.4)			(6.7)	(139.1)
Stock options and awards	86.0	0.7	84.7			0.6		86.0
Reacquired shares	(216.0)					(216.0)		(216.0)
Balance at Jun. 30, 2019	$ 8,225.4	$ 358.9	$ 5,815.7	$ 9,368.0	$ (1,836.4)	$ (5,480.8)	$ 44.0	$ 8,269.4