Guarantor Financial Information - Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Cash Flow Statements, Captions [Line Items]
Cash flow (used in) provided by operating activities	$ 108	$ 70
Cash flows from investing activities
Additions to property, plant and equipment	(30)	(27)
Acquisitions, net of cash required	(67)	(48)
Proceeds from sale of operations	5	0
Other investing activities, net	1	(1)
Return of advance from subsidiary	0	0
Total cash used in investing activities	(91)	(76)
Cash flows from financing activities
Net transfers to Ashland	0	(2)
Proceeds from borrowings, net of issuance costs	95	75
Repayments on borrowings	(15)	(83)
Repurchases of common stock	(123)	0
Purchase of additional ownership in subsidiary	(15)
Cash dividends paid	(30)	(20)
Other financing activities	(5)	0
Other intercompany activity, net	0	0
Total cash used in financing activities	(93)	(30)
Effect of currency exchange rate changes on cash and cash equivalents	2	(1)
Decrease in cash and cash equivalents	(74)	(37)
Cash and cash equivalents - beginning of period	201	172
Cash and cash equivalents - end of period	127	135
Reportable Legal Entities | Valvoline Inc. (Parent Issuer)
Condensed Cash Flow Statements, Captions [Line Items]
Cash flow (used in) provided by operating activities	(24)	93
Cash flows from investing activities
Additions to property, plant and equipment	0	0
Acquisitions, net of cash required	0	0
Proceeds from sale of operations	0
Other investing activities, net	0	0
Return of advance from subsidiary	187	10
Total cash used in investing activities	187	10
Cash flows from financing activities
Net transfers to Ashland		(2)
Proceeds from borrowings, net of issuance costs	6	0
Repayments on borrowings	(14)	(83)
Repurchases of common stock	(123)
Purchase of additional ownership in subsidiary	0
Cash dividends paid	(30)	(20)
Other financing activities	(2)
Other intercompany activity, net	0	2
Total cash used in financing activities	(163)	(103)
Effect of currency exchange rate changes on cash and cash equivalents	0	0
Decrease in cash and cash equivalents	0	0
Cash and cash equivalents - beginning of period	0	0
Cash and cash equivalents - end of period	0	0
Reportable Legal Entities | Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Cash flow (used in) provided by operating activities	199	39
Cash flows from investing activities
Additions to property, plant and equipment	(28)	(27)
Acquisitions, net of cash required	(67)	(48)
Proceeds from sale of operations	5
Other investing activities, net	1	(1)
Return of advance from subsidiary	0	0
Total cash used in investing activities	(89)	(76)
Cash flows from financing activities
Net transfers to Ashland		0
Proceeds from borrowings, net of issuance costs	0	0
Repayments on borrowings	0	0
Repurchases of common stock	0
Purchase of additional ownership in subsidiary	0
Cash dividends paid	0	0
Other financing activities	(1)
Other intercompany activity, net	(187)	(12)
Total cash used in financing activities	(188)	(12)
Effect of currency exchange rate changes on cash and cash equivalents	0	0
Decrease in cash and cash equivalents	(78)	(49)
Cash and cash equivalents - beginning of period	99	93
Cash and cash equivalents - end of period	21	44
Reportable Legal Entities | Non-Guarantor Subsidiaries
Condensed Cash Flow Statements, Captions [Line Items]
Cash flow (used in) provided by operating activities	(67)	(62)
Cash flows from investing activities
Additions to property, plant and equipment	(2)	0
Acquisitions, net of cash required	0	0
Proceeds from sale of operations	0
Other investing activities, net	0	0
Return of advance from subsidiary	0	0
Total cash used in investing activities	(2)	0
Cash flows from financing activities
Net transfers to Ashland		0
Proceeds from borrowings, net of issuance costs	89	75
Repayments on borrowings	(1)	0
Repurchases of common stock	0
Purchase of additional ownership in subsidiary	(15)
Cash dividends paid	0	0
Other financing activities	(2)
Other intercompany activity, net	0	0
Total cash used in financing activities	71	75
Effect of currency exchange rate changes on cash and cash equivalents	2	(1)
Decrease in cash and cash equivalents	4	12
Cash and cash equivalents - beginning of period	102	79
Cash and cash equivalents - end of period	106	91
Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Cash flow (used in) provided by operating activities	0	0
Cash flows from investing activities
Additions to property, plant and equipment	0	0
Acquisitions, net of cash required	0	0
Proceeds from sale of operations	0
Other investing activities, net	0	0
Return of advance from subsidiary	(187)	(10)
Total cash used in investing activities	(187)	(10)
Cash flows from financing activities
Net transfers to Ashland		0
Proceeds from borrowings, net of issuance costs	0	0
Repayments on borrowings	0	0
Repurchases of common stock	0
Purchase of additional ownership in subsidiary	0
Cash dividends paid	0	0
Other financing activities	0
Other intercompany activity, net	187	10
Total cash used in financing activities	187	10
Effect of currency exchange rate changes on cash and cash equivalents	0	0
Decrease in cash and cash equivalents	0	0
Cash and cash equivalents - beginning of period	0	0
Cash and cash equivalents - end of period	$ 0	$ 0