Stock-Based Compensation Plans - Narrative (Details) $ / shares in Units, $ in Millions	12 Months Ended
Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) $ / shares
Stock appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unexercised SARs lapsing period	10 years
Unrecognized compensation costs	$ 1
Unrecognized compensation costs weighted average period related to nonvested awards	1 year 7 months 25 days
Stock appreciation rights \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Stock appreciation rights \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Nonvested stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs	$ 9
Unrecognized compensation costs weighted average period related to nonvested awards	2 years 6 months 20 days
Grant date fair values of shares vested	$ 6	$ 1
Aggregate intrinsic value	$ 27
Granted, weighted average grant date fair value (in usd per share) \| $ / shares	$ 23.17	$ 22.82
Nonvested stock awards \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year
Nonvested stock awards \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Performance awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Unrecognized compensation costs	$ 1
Unrecognized compensation costs weighted average period related to nonvested awards	1 year 9 months
Aggregate intrinsic value	$ 7
Granted, weighted average grant date fair value (in usd per share) \| $ / shares	$ 23.82	$ 18.44
Valvoline Inc. Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the plan (in shares) \| shares	11,000,000
Number of shares remaining under the plan (in shares) \| shares	7,000,000
Reduction of authorized shares, conversion ratio	4.5

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Stockholders' Equity Note, Reduction In Authorized Shares, Conversion Ratio

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