Guarantor Financial Information - Condensed Consolidating Statements of Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2020	Mar. 31, 2019
Net Income (Loss) Attributable to Parent [Abstract]
Sales	$ 578		$ 591		$ 1,185	$ 1,148
Cost of sales	371		388		767	762
Gross profit	207		203		418	386
Selling, general and administrative expenses	96		113		213	218
Net legacy and separation-related expenses (income)	0		3		(1)	3
Equity and other (income) expenses, net	(6)		(9)		(15)	(18)
Operating income	117		96		221	183
Net pension and other postretirement plan income	(9)		(3)		(18)	(5)
Net interest and other financing expenses	38		19		54	36
Income before income taxes	88		80		185	152
Income tax (benefit) expense	25		17		49	36
Equity in net income of subsidiaries	0		0		0	0
Net income	63	$ 73	63	$ 53	136	116
Comprehensive income	40		63		119	110
Eliminations
Net Income (Loss) Attributable to Parent [Abstract]
Sales	(12)		(17)		(25)	(32)
Cost of sales	(12)		(17)		(25)	(32)
Gross profit	0		0		0	0
Selling, general and administrative expenses	0		0		0	0
Net legacy and separation-related expenses (income)			0		0	0
Equity and other (income) expenses, net	0		0		0	0
Operating income	0		0		0	0
Net pension and other postretirement plan income	0		0		0	0
Net interest and other financing expenses	0		0		0	0
Income before income taxes	0		0		0	0
Income tax (benefit) expense	0		0		0	0
Equity in net income of subsidiaries	95		85		188	157
Net income	(95)		(85)		(188)	(157)
Comprehensive income	(54)		(86)		(158)	(148)
Valvoline Inc. (Parent Issuer) | Reportable Legal Entities
Net Income (Loss) Attributable to Parent [Abstract]
Sales	0		0		0	0
Cost of sales	0		0		0	0
Gross profit	0		0		0	0
Selling, general and administrative expenses	(1)		2		3	5
Net legacy and separation-related expenses (income)			3		(1)	3
Equity and other (income) expenses, net	0		0		0	0
Operating income	1		(5)		(2)	(8)
Net pension and other postretirement plan income	0		0		0	0
Net interest and other financing expenses	36		15		51	30
Income before income taxes	(35)		(20)		(53)	(38)
Income tax (benefit) expense	(8)		(6)		(14)	(11)
Equity in net income of subsidiaries	(90)		(77)		(175)	(143)
Net income	63		63		136	116
Comprehensive income	40		63		119	110
Guarantor Subsidiaries | Reportable Legal Entities
Net Income (Loss) Attributable to Parent [Abstract]
Sales	468		465		948	905
Cost of sales	297		300		606	593
Gross profit	171		165		342	312
Selling, general and administrative expenses	75		90		163	171
Net legacy and separation-related expenses (income)			0		0	0
Equity and other (income) expenses, net	(13)		(14)		(26)	(27)
Operating income	109		89		205	168
Net pension and other postretirement plan income	(9)		(3)		(18)	(5)
Net interest and other financing expenses	2		2		3	3
Income before income taxes	116		90		220	170
Income tax (benefit) expense	31		21		58	41
Equity in net income of subsidiaries	(5)		(8)		(13)	(14)
Net income	90		77		175	143
Comprehensive income	69		77		158	137
Non-Guarantor Subsidiaries | Reportable Legal Entities
Net Income (Loss) Attributable to Parent [Abstract]
Sales	122		143		262	275
Cost of sales	86		105		186	201
Gross profit	36		38		76	74
Selling, general and administrative expenses	22		21		47	42
Net legacy and separation-related expenses (income)			0		0	0
Equity and other (income) expenses, net	7		5		11	9
Operating income	7		12		18	23
Net pension and other postretirement plan income	0		0		0	0
Net interest and other financing expenses	0		2		0	3
Income before income taxes	7		10		18	20
Income tax (benefit) expense	2		2		5	6
Equity in net income of subsidiaries	0		0		0	0
Net income	5		8		13	14
Comprehensive income	$ (15)		$ 9		$ 0	$ 11