OPERATING SEGMENTS AND GEOGRAPHIC INFORMATION (Details) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Financial information of reportable segments
Number of operating units \| segment									11
Number of reportable segments \| segment									3
Net sales	$ 3,065.3	$ 3,018.6	$ 2,685.7	$ 3,020.6	$ 3,244.2	$ 3,224.0	$ 3,169.1	$ 2,924.7	$ 11,790.2	$ 12,562.0	$ 12,222.1
Operating Income (Loss)	$ 416.1	$ 411.4	$ 192.0	$ 376.2	$ 518.2	$ 549.0	$ 464.4	$ 313.6	1,395.7	1,845.2	1,728.3
Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									11,790.2	12,562.0	12,222.1
Operating Income (Loss)									1,395.7	1,845.2	1,728.3
Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Net sales										14,906.3	14,668.2
Operating Income (Loss)										2,013.8	1,947.0
Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										14,906.3	14,668.2
Operating Income (Loss)										2,013.8	1,947.0
Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Net sales										(2,344.3)	(2,446.1)
Operating Income (Loss)										(168.6)	(218.7)
Global Industrial
Financial information of reportable segments
Net sales									5,870.8	5,980.2	5,806.8
Global Institutional & Specialty
Financial information of reportable segments
Net sales									3,553.2	4,401.5	4,302.0
Global Healthcare and Life Sciences
Financial information of reportable segments
Net sales									1,181.9	972.8	939.5
Global Healthcare and Life Sciences \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										979.0
Global Healthcare and Life Sciences \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										979.0
Global Healthcare and Life Sciences \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales										991.7
Global Healthcare and Life Sciences \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales										(12.7)
Upstream Energy \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										2,352.9
Upstream Energy \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales										2,350.0
Upstream Energy \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales										2.9
Upstream Energy \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Net sales										(2,352.9)
Other
Financial information of reportable segments
Net sales									1,084.3	1,207.5	1,173.8
Operating segment \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									11,921.9	12,597.4	12,014.7
Operating Income (Loss)									1,419.5	1,854.3	1,701.8
Operating segment \| Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Net sales										15,046.9	14,530.7
Operating Income (Loss)										2,034.2	1,926.6
Operating segment \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										14,952.1	14,438.8
Operating Income (Loss)										2,023.6	1,918.3
Operating segment \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales										(94.8)	(91.9)
Operating Income (Loss)										(10.6)	(8.3)
Operating segment \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Net sales										(2,354.7)	(2,424.1)
Operating Income (Loss)										(169.3)	(216.5)
Operating segment \| Global Industrial \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									5,959.9	5,994.6	5,688.5
Operating Income (Loss)									1,106.0	902.7	753.7
Operating segment \| Global Industrial \| Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Net sales										5,569.9	5,220.2
Operating Income (Loss)										854.7	724.4
Operating segment \| Global Industrial \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										5,996.4	5,690.3
Operating Income (Loss)										980.6	834.0
Operating segment \| Global Industrial \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales										479.2	520.9
Operating Income (Loss)										133.4	116.2
Operating segment \| Global Industrial \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales										(52.7)	(50.8)
Operating Income (Loss)										(7.5)	(6.6)
Operating segment \| Global Industrial \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Net sales										(1.8)	(1.8)
Operating Income (Loss)										(77.9)	(80.3)
Operating segment \| Global Institutional & Specialty \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									3,577.2	4,412.1	4,255.2
Operating Income (Loss)									321.9	939.8	901.5
Operating segment \| Global Institutional & Specialty \| Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Net sales										5,235.5	5,066.0
Operating Income (Loss)										1,042.2	1,007.3
Operating segment \| Global Institutional & Specialty \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										4,412.1	4,255.2
Operating Income (Loss)										947.3	905.0
Operating segment \| Global Institutional & Specialty \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales										(800.1)	(788.3)
Operating Income (Loss)										(93.4)	(100.8)
Operating segment \| Global Institutional & Specialty \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales										(23.3)	(22.5)
Operating Income (Loss)										(1.5)	(1.5)
Operating segment \| Global Institutional & Specialty \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Operating Income (Loss)										(7.5)	(3.5)
Operating segment \| Global Healthcare and Life Sciences \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									1,189.1	979.0	915.7
Operating Income (Loss)									207.6	124.5	124.4
Operating segment \| Global Healthcare and Life Sciences \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales											915.7
Operating Income (Loss)										135.1	135.1
Operating segment \| Global Healthcare and Life Sciences \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales											928.2
Operating Income (Loss)										136.7	136.8
Operating segment \| Global Healthcare and Life Sciences \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales											(12.5)
Operating Income (Loss)										(1.6)	(1.7)
Operating segment \| Global Healthcare and Life Sciences \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Operating Income (Loss)										(10.6)	(10.7)
Operating segment \| Upstream Energy \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales											2,422.3
Operating Income (Loss)										187.9
Operating segment \| Upstream Energy \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales											2,419.8
Operating Income (Loss)										188.2
Operating segment \| Upstream Energy \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales											2.5
Operating Income (Loss)										(0.3)
Operating segment \| Upstream Energy \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Net sales											(2,422.3)
Operating Income (Loss)										(187.9)
Operating segment \| Global Energy \| Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Net sales										3,334.0	3,388.8
Operating Income (Loss)										379.1	338.5
Operating segment \| Global Energy \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales										(3,334.0)	(3,388.8)
Operating Income (Loss)										(379.1)	(338.5)
Operating segment \| Other \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									1,093.3	1,211.7	1,155.3
Operating Income (Loss)									131.5	167.0	164.0
Operating segment \| Other \| Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Net sales										907.5	855.7
Operating Income (Loss)										167.3	160.0
Operating segment \| Other \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										1,211.7	1,155.3
Operating Income (Loss)										180.6	174.6
Operating segment \| Other \| Adjustment \| Segment Change
Financial information of reportable segments
Net sales										313.2	308.2
Operating Income (Loss)										14.2	15.6
Operating segment \| Other \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales										(9.0)	(8.6)
Operating Income (Loss)										(0.9)	(1.0)
Operating segment \| Other \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Operating Income (Loss)										(13.6)	(10.6)
Currency Impact \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									(131.7)	(35.4)	207.4
Operating Income (Loss)									(23.8)	(9.1)	26.5
Currency Impact \| Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Net sales										(140.6)	137.5
Operating Income (Loss)										(20.4)	20.4
Currency Impact \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales										(45.8)	229.4
Operating Income (Loss)										(9.8)	28.7
Currency Impact \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Net sales										94.8	91.9
Operating Income (Loss)										10.6	8.3
Currency Impact \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Net sales										10.4	(22.0)
Operating Income (Loss)										0.7	(2.2)
Corporate
Financial information of reportable segments
Net sales									100.0
Corporate \| Valued at 2020 Management Rates
Financial information of reportable segments
Net sales									102.4
Operating Income (Loss)									$ (347.5)	(279.7)	(241.8)
Corporate \| Previously Reported \| Valued at 2019 Management Rates
Financial information of reportable segments
Operating Income (Loss)										(409.1)	(303.6)
Corporate \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Operating Income (Loss)										(407.9)	(302.7)
Corporate \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Operating Income (Loss)										1.2	0.9
Corporate \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Operating Income (Loss)										$ 128.2	60.9
Corporate \| Upstream Energy \| Previously Reported \| Valued at 2020 Management Rates
Financial information of reportable segments
Operating Income (Loss)											172.3
Corporate \| Upstream Energy \| Adjustment \| Segment Change
Financial information of reportable segments
Operating Income (Loss)											170.7
Corporate \| Upstream Energy \| Adjustment \| Fixed Currency Rate Change
Financial information of reportable segments
Operating Income (Loss)											1.6
Corporate \| Upstream Energy \| Adjustment \| Discontinued Operations and Related Allocation Charges
Financial information of reportable segments
Operating Income (Loss)											$ (172.3)