OPERATING SEGMENTS (Details) € in Millions, $ in Millions	3 Months Ended				12 Months Ended
	Mar. 31, 2019 EUR (€) item	Mar. 31, 2019 USD ($) item	Mar. 31, 2018 EUR (€)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Financial information of reportable segments
Number of reportable segments | item	3	3
Net sales		$ 3,505.4		$ 3,470.9	$ 14,668.2
Operating Income (Loss)		367.2		354.3	1,947.0
Previously Reported
Financial information of reportable segments
Net sales					14,668.2
Operating Income (Loss)					1,947.0
Global Industrial
Financial information of reportable segments
Net sales | €	€ 1,281.3		€ 1,225.9
Global Institutional
Financial information of reportable segments
Net sales | €	1,208.5		1,206.3
Global Energy
Financial information of reportable segments
Net sales | €	809.4		842.9
Other
Financial information of reportable segments
Net sales | €	€ 206.2		€ 195.8
Operating segment
Financial information of reportable segments
Net sales		3,523.0		3,396.1	14,530.7
Operating Income (Loss)		368.3		345.1	1,926.6
Operating segment | Previously Reported
Financial information of reportable segments
Net sales					15,046.3
Operating Income (Loss)					2,007.7
Operating segment | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales					(515.6)
Operating Income (Loss)					(81.1)
Operating segment | Global Industrial
Financial information of reportable segments
Net sales		1,289.2		1,190.2	5,220.2
Operating Income (Loss)		147.5		122.0	724.4
Operating segment | Global Industrial | Previously Reported
Financial information of reportable segments
Net sales					5,462.4
Operating Income (Loss)					768.1
Operating segment | Global Industrial | Adjustment | Segment Change
Financial information of reportable segments
Operating Income (Loss)					(1.4)
Operating segment | Global Industrial | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales					(242.2)
Operating Income (Loss)					(42.3)
Operating segment | Global Institutional
Financial information of reportable segments
Net sales		1,215.3		1,187.0	5,066.0
Operating Income (Loss)		195.9		195.7	1,007.3
Operating segment | Global Institutional | Previously Reported
Financial information of reportable segments
Net sales					5,204.5
Operating Income (Loss)					1,026.9
Operating segment | Global Institutional | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales					(138.5)
Operating Income (Loss)					(19.6)
Operating segment | Global Energy
Financial information of reportable segments
Net sales		811.7		826.5	3,388.8
Operating Income (Loss)		78.4		68.6	338.5
Operating segment | Global Energy | Previously Reported
Financial information of reportable segments
Net sales					3,501.8
Operating Income (Loss)					358.5
Operating segment | Global Energy | Adjustment | Segment Change
Financial information of reportable segments
Operating Income (Loss)					(0.4)
Operating segment | Global Energy | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales					(113.0)
Operating Income (Loss)					(19.6)
Operating segment | Other
Financial information of reportable segments
Net sales		206.8		192.4	855.7
Operating Income (Loss)		30.2		27.0	160.0
Operating segment | Other | Previously Reported
Financial information of reportable segments
Net sales					877.6
Operating Income (Loss)					161.3
Operating segment | Other | Adjustment | Segment Change
Financial information of reportable segments
Operating Income (Loss)					1.8
Operating segment | Other | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales					(21.9)
Operating Income (Loss)					(3.1)
Currency Impact
Financial information of reportable segments
Net sales		(17.6)		74.8	137.5
Operating Income (Loss)		(1.1)		9.2	20.4
Currency Impact | Previously Reported
Financial information of reportable segments
Net sales					(378.1)
Operating Income (Loss)					(60.7)
Currency Impact | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales					515.6
Operating Income (Loss)					81.1
Corporate
Financial information of reportable segments
Operating Income (Loss)		$ (83.7)		$ (68.2)	(303.6)
Corporate | Previously Reported
Financial information of reportable segments
Operating Income (Loss)					(307.1)
Corporate | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Operating Income (Loss)					$ 3.5