OPERATING SEGMENTS (Details) € in Millions, $ in Millions	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2019 EUR (€)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 EUR (€)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) item	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Financial information of reportable segments
Number of reportable segments | item					3
Net sales		$ 3,759.4		$ 3,689.6	$ 7,264.8	$ 7,160.5	$ 14,668.2
Operating Income (Loss)		498.6		494.6	865.8	848.9	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	€ 1,380.8		€ 1,327.3		2,662.1	2,553.2
Global Institutional
Financial information of reportable segments
Net sales	1,311.8		1,296.6		2,520.3	2,502.9
Global Energy
Financial information of reportable segments
Net sales	837.4		845.2		1,646.8	1,688.1
Other
Financial information of reportable segments
Net sales	€ 229.4		€ 220.5		435.6	416.3
Operating segment
Financial information of reportable segments
Net sales		3,788.3		3,615.5	7,311.3	7,011.6	14,530.7
Operating Income (Loss)		503.0		481.2	871.3	826.3	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		1,393.9		1,290.2	2,683.1	2,480.4	5,220.2
Operating Income (Loss)		208.7		162.8	356.2	284.8	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		1,323.5		1,277.5	2,538.8	2,464.5	5,066.0
Operating Income (Loss)		258.9		247.0	454.8	442.7	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		840.4		831.0	1,652.1	1,657.5	3,388.8
Operating Income (Loss)		88.9		86.4	167.3	155.0	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		230.5		216.8	437.3	409.2	855.7
Operating Income (Loss)		44.1		39.0	74.3	66.0	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		(28.9)		74.1	(46.5)	148.9	137.5
Operating Income (Loss)		(4.4)		13.4	(5.5)	22.6	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)		$ (97.6)		$ (54.0)	$ (181.3)	$ (122.2)	(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