Goodwill and Other Intangibles - Definite-Lived Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2015
Finite-Lived Intangible Assets Line Items
Gross Carrying Amount	$ 156.5		$ 156.5		$ 156.6
Accumulated Amortization	(53.0)		(53.0)		(45.2)
Net Carrying Amount	103.5		103.5		111.4
Amortization of intangible assets	3.9	$ 3.9	$ 7.8	$ 7.9
Archway Sales, Inc.
Finite-Lived Intangible Assets Line Items
Non-Compete agreement, term			5 years
Customer-related intangibles
Finite-Lived Intangible Assets Line Items
Gross Carrying Amount	121.2		$ 121.2		121.3
Accumulated Amortization	(38.9)		(38.9)		(33.6)
Net Carrying Amount	82.3		$ 82.3		87.7
Customer-related intangibles \| Minimum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			5 years
Customer-related intangibles \| Maximum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			14 years
Customer-related intangibles \| Ashland Distribution Acquisition
Finite-Lived Intangible Assets Line Items
Net Carrying Amount	44.3		$ 44.3		46.8
Customer-related intangibles \| Beijing Plaschem
Finite-Lived Intangible Assets Line Items
Net Carrying Amount	1.6		1.6		2.2
Customer-related intangibles \| CSD
Finite-Lived Intangible Assets Line Items
Net Carrying Amount	27.6		27.6		29.4
Customer-related intangibles \| Archway Sales, Inc.
Finite-Lived Intangible Assets Line Items
Net Carrying Amount	8.8		$ 8.8		9.3
Supplier-related intangible
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			10 years
Gross Carrying Amount	17.0		$ 17.0		17.0
Accumulated Amortization	(3.4)		(3.4)		(2.6)
Net Carrying Amount	13.6		13.6		14.4
Leasehold interest intangible
Finite-Lived Intangible Assets Line Items
Gross Carrying Amount	2.1		2.1		2.1
Accumulated Amortization	(1.4)		(1.4)		(1.3)
Net Carrying Amount	0.7		$ 0.7		0.8
Leasehold interest intangible \| Minimum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			1 year
Leasehold interest intangible \| Maximum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			20 years
Non-compete agreements
Finite-Lived Intangible Assets Line Items
Gross Carrying Amount	10.0		$ 10.0		10.0
Accumulated Amortization	(5.3)		(5.3)		(4.5)
Net Carrying Amount	4.7		$ 4.7		5.5
Non-compete agreements \| Minimum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			3 years
Non-compete agreements \| Maximum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			5 years
Non-compete agreements \| Ashland Distribution Acquisition
Finite-Lived Intangible Assets Line Items
Non-Compete agreement, term			3 years
Non-compete agreements \| CSD
Finite-Lived Intangible Assets Line Items
Non-Compete agreement, term			5 years
Trademarks and trade names
Finite-Lived Intangible Assets Line Items
Gross Carrying Amount	6.2		$ 6.2		6.2
Accumulated Amortization	(4.0)		(4.0)		(3.2)
Net Carrying Amount	2.2		$ 2.2		3.0
Trademarks and trade names \| Minimum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			2 years
Trademarks and trade names \| Maximum
Finite-Lived Intangible Assets Line Items
Estimated Useful Life (years)			6 years
Trademarks and trade names \| CSD
Finite-Lived Intangible Assets Line Items
Net Carrying Amount	$ 2.2		$ 2.2		2.4
Trademarks and trade names \| Archway Sales, Inc.
Finite-Lived Intangible Assets Line Items
Net Carrying Amount					$ 0.6

Nexeo Solutions Holdings, LLC 10-Q