Discontinued operations and dispositions (Details) $ in Millions			6 Months Ended
	Dec. 31, 2019 USD ($)	Mar. 29, 2019 USD ($) renewal	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition services agreement, number of renewals | renewal		2
Proceeds from sale of Environmental Sciences business			$ (8.2)	$ 640.0
Nexeo Plastics
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of plastics distribution business		$ 664.3
Net of cash disposed		2.4
Total excess working capital		$ 26.7
Transition services agreement, term of renewals		12 months
Environmental Sciences Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business	$ 41.4
Environmental Sciences Business | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total excess working capital					$ 8.2
Proceeds from sale of Environmental Sciences business	174.0
Cash disposed in sale of Environmental Sciences business	0.7
Transaction expenses from sale of Environmental Sciences business	5.9
Non-cash proceeds from sale	5.0
Present values of notes receivables	$ 2.4
Minimum | Nexeo Plastics
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition services agreement, contract term		6 months
Maximum | Nexeo Plastics
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition services agreement, contract term		24 months
Real property agreement, contract term		3 years