Guarantor Financial Information - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows (used in) provided by operating activities	$ 320	$ (130)	$ 311
Cash flows from investing activities
Additions to property, plant and equipment	(93)	(68)	(66)
Acquisitions, net of cash acquired	(125)	(68)	(83)
Other investing activities, net	5	1	1
Return of advance from subsidiary	0	0
Total cash used in investing activities	(213)	(135)	(148)
Cash flows from financing activities
Net transfers from (to) Ashland	0	5	(1,504)
Cash contributions from Ashland	0	0	60
Proceeds from initial public offering, net of offering costs of $40	0	0	719
Proceeds from borrowings, net of issuance costs	304	470	1,372
Repayments on borrowings	(108)	(90)	(637)
Repurchases of common stock	(325)	(50)	0
Purchase of additional ownership in subsidiary	(15)
Cash dividends paid	(58)	(40)	0
Other financing activities	(7)	0	0
Other intercompany activity, net	0	0	0
Total cash (used in) provided by financing activities	(209)	295	10
Effect of currency exchange rate changes on cash and cash equivalents	(3)	(1)	(1)
(Decrease) increase in cash and cash equivalents	(105)	29	172
Cash and cash equivalents - beginning of year	201	172	0
Cash and cash equivalents - end of year	96	201	172
Reportable Legal Entities | Valvoline Inc. (Parent Issuer)
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows (used in) provided by operating activities	(57)	97	(35)
Cash flows from investing activities
Additions to property, plant and equipment	0	0	0
Acquisitions, net of cash acquired	0	0	0
Other investing activities, net	0	0	0
Return of advance from subsidiary	312	(312)
Total cash used in investing activities	312	(312)	0
Cash flows from financing activities
Net transfers from (to) Ashland		5	(1,504)
Cash contributions from Ashland			60
Proceeds from initial public offering, net of offering costs of $40			719
Proceeds from borrowings, net of issuance costs	203	395	1,372
Repayments on borrowings	(72)	(90)	(637)
Repurchases of common stock	(325)	(50)
Purchase of additional ownership in subsidiary	0
Cash dividends paid	(58)	(40)
Other financing activities	(3)
Other intercompany activity, net	0	(5)	25
Total cash (used in) provided by financing activities	(255)	215	35
Effect of currency exchange rate changes on cash and cash equivalents	0	0	0
(Decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents - beginning of year	0	0	0
Cash and cash equivalents - end of year	0	0	0
Reportable Legal Entities | Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows (used in) provided by operating activities	390	(180)	307
Cash flows from investing activities
Additions to property, plant and equipment	(88)	(64)	(60)
Acquisitions, net of cash acquired	(72)	(68)	(83)
Other investing activities, net	5	1	1
Return of advance from subsidiary	0	0
Total cash used in investing activities	(155)	(131)	(142)
Cash flows from financing activities
Net transfers from (to) Ashland		0	0
Cash contributions from Ashland			0
Proceeds from initial public offering, net of offering costs of $40			0
Proceeds from borrowings, net of issuance costs	0	0	0
Repayments on borrowings	0	0	0
Repurchases of common stock	0	0
Purchase of additional ownership in subsidiary	0
Cash dividends paid	0	0
Other financing activities	(2)
Other intercompany activity, net	(312)	317	(72)
Total cash (used in) provided by financing activities	(314)	317	(72)
Effect of currency exchange rate changes on cash and cash equivalents	0	0	0
(Decrease) increase in cash and cash equivalents	(79)	6	93
Cash and cash equivalents - beginning of year	99	93	0
Cash and cash equivalents - end of year	20	99	93
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows (used in) provided by operating activities	(13)	(47)	39
Cash flows from investing activities
Additions to property, plant and equipment	(5)	(4)	(6)
Acquisitions, net of cash acquired	(53)	0	0
Other investing activities, net	0	0	0
Return of advance from subsidiary	0	0
Total cash used in investing activities	(58)	(4)	(6)
Cash flows from financing activities
Net transfers from (to) Ashland		0	0
Cash contributions from Ashland			0
Proceeds from initial public offering, net of offering costs of $40			0
Proceeds from borrowings, net of issuance costs	101	75	0
Repayments on borrowings	(36)	0	0
Repurchases of common stock	0	0
Purchase of additional ownership in subsidiary	(15)
Cash dividends paid	0	0
Other financing activities	(2)
Other intercompany activity, net	0	0	47
Total cash (used in) provided by financing activities	48	75	47
Effect of currency exchange rate changes on cash and cash equivalents	(3)	(1)	(1)
(Decrease) increase in cash and cash equivalents	(26)	23	79
Cash and cash equivalents - beginning of year	102	79	0
Cash and cash equivalents - end of year	76	102	79
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Cash flows (used in) provided by operating activities	0	0	0
Cash flows from investing activities
Additions to property, plant and equipment	0	0	0
Acquisitions, net of cash acquired	0	0	0
Other investing activities, net	0	0	0
Return of advance from subsidiary	(312)	312
Total cash used in investing activities	(312)	312	0
Cash flows from financing activities
Net transfers from (to) Ashland		0	0
Cash contributions from Ashland			0
Proceeds from initial public offering, net of offering costs of $40			0
Proceeds from borrowings, net of issuance costs	0	0	0
Repayments on borrowings	0	0	0
Repurchases of common stock	0	0
Purchase of additional ownership in subsidiary	0
Cash dividends paid	0	0
Other financing activities	0
Other intercompany activity, net	312	(312)	0
Total cash (used in) provided by financing activities	312	(312)	0
Effect of currency exchange rate changes on cash and cash equivalents	0	0	0
(Decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents - beginning of year	0	0	0
Cash and cash equivalents - end of year	$ 0	$ 0	$ 0