OPERATING SEGMENTS (Details) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2020 USD ($) item	Mar. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)
Financial information of reportable segments
Number of reportable segments | item	4
Net sales	$ 3,581.4	$ 3,505.4	$ 14,906.3
Operating Income (Loss)	397.2	367.2	2,013.8
Previously Reported
Financial information of reportable segments
Net sales			14,906.3
Operating Income (Loss)			2,013.8
Global Industrial
Financial information of reportable segments
Net sales	1,434.5	1,402.0
Global Institutional
Financial information of reportable segments
Net sales	1,067.2	1,020.8
Global Healthcare and Life Sciences
Financial information of reportable segments
Net sales	243.6	227.6
Upstream Energy
Financial information of reportable segments
Net sales	560.4	580.0
Other
Financial information of reportable segments
Net sales	275.7	275.0
Operating segment
Financial information of reportable segments
Net sales	3,603.0	3,501.0	14,952.1
Operating Income (Loss)	400.1	366.7	2,023.6
Operating segment | Previously Reported
Financial information of reportable segments
Net sales			15,046.9
Operating Income (Loss)			2,034.2
Operating segment | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales			(94.8)
Operating Income (Loss)			(10.6)
Operating segment | Global Industrial
Financial information of reportable segments
Net sales	1,444.0	1,397.4	5,996.4
Operating Income (Loss)	226.9	181.2	980.6
Operating segment | Global Industrial | Previously Reported
Financial information of reportable segments
Net sales			5,569.9
Operating Income (Loss)			854.7
Operating segment | Global Industrial | Adjustment | Segment Change
Financial information of reportable segments
Net sales			479.2
Operating Income (Loss)			133.4
Operating segment | Global Industrial | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales			(52.7)
Operating Income (Loss)			(7.5)
Operating segment | Global Institutional
Financial information of reportable segments
Net sales	1,072.3	1,020.2	4,412.1
Operating Income (Loss)	183.5	176.2	947.3
Operating segment | Global Institutional | Previously Reported
Financial information of reportable segments
Net sales			5,235.5
Operating Income (Loss)			1,042.2
Operating segment | Global Institutional | Adjustment | Segment Change
Financial information of reportable segments
Net sales			(800.1)
Operating Income (Loss)			(93.4)
Operating segment | Global Institutional | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales			(23.3)
Operating Income (Loss)			(1.5)
Operating segment | Global Healthcare and Life Sciences
Financial information of reportable segments
Net sales	246.2	227.0	979.0
Operating Income (Loss)	25.6	27.3	135.1
Operating segment | Global Healthcare and Life Sciences | Adjustment | Segment Change
Financial information of reportable segments
Net sales			991.7
Operating Income (Loss)			136.7
Operating segment | Global Healthcare and Life Sciences | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales			(12.7)
Operating Income (Loss)			(1.6)
Operating segment | Upstream Energy
Financial information of reportable segments
Net sales	562.7	581.7	2,352.9
Operating Income (Loss)	39.0	36.5	187.9
Operating segment | Upstream Energy | Adjustment | Segment Change
Financial information of reportable segments
Net sales			2,350.0
Operating Income (Loss)			188.2
Operating segment | Upstream Energy | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales			2.9
Operating Income (Loss)			(0.3)
Operating segment | Global Energy | Previously Reported
Financial information of reportable segments
Net sales			3,334.0
Operating Income (Loss)			379.1
Operating segment | Global Energy | Adjustment | Segment Change
Financial information of reportable segments
Net sales			(3,334.0)
Operating Income (Loss)			(379.1)
Operating segment | Other
Financial information of reportable segments
Net sales	277.8	274.7	1,211.7
Operating Income (Loss)	25.3	28.9	180.6
Operating segment | Other | Previously Reported
Financial information of reportable segments
Net sales			907.5
Operating Income (Loss)			167.3
Operating segment | Other | Adjustment | Segment Change
Financial information of reportable segments
Net sales			313.2
Operating Income (Loss)			14.2
Operating segment | Other | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales			(9.0)
Operating Income (Loss)			(0.9)
Currency Impact
Financial information of reportable segments
Net sales	(21.6)	4.4	(45.8)
Operating Income (Loss)	(2.9)	0.5	(9.8)
Currency Impact | Previously Reported
Financial information of reportable segments
Net sales			(140.6)
Operating Income (Loss)			(20.4)
Currency Impact | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Net sales			94.8
Operating Income (Loss)			10.6
Corporate
Financial information of reportable segments
Operating Income (Loss)	$ (100.2)	$ (83.4)	(407.9)
Corporate | Previously Reported
Financial information of reportable segments
Operating Income (Loss)			(409.1)
Corporate | Adjustment | Fixed Currency Rate Change
Financial information of reportable segments
Operating Income (Loss)			$ 1.2