Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

Income Taxes - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Contingency [Line Items]
Income tax expense	$ 33	$ 38	$ 154	$ 114
Effective tax rate	34.00%	40.40%	56.00%	36.40%
Tax cuts and jobs act of 2017, income tax expense (benefit)			$ 76
Increase in income tax resulting from U.S. tax reform legislation			69
Repatriation tax on unremitted non-U.S. earnings			4
Estimated incremental withholding taxes	$ 2		2
Net deferred tax assets						$ 281
Gross liability	23		23
Foreign tax credits			19
Liability for uncertain income tax positions	11		11
Tax Matters Agreement \| Ashland
Income Tax Contingency [Line Items]
Due to (from) related party	78		78			74
Tax Matters Agreement \| Ashland \| Accrued expenses and other liabilities
Income Tax Contingency [Line Items]
Due to (from) related party	3		3			2
Ashland \| Tax Matters Agreement \| Ashland
Income Tax Contingency [Line Items]
Tax cuts and jobs act of 2017, income tax expense (benefit)			(3)
Increase (decrease) in due to affiliates recognized in selling, general and administrative expense			7
Due to (from) related party	65		65			62
Ashland \| Tax Matters Agreement \| Ashland \| Accrued expenses and other liabilities
Income Tax Contingency [Line Items]
Due to (from) related party	3		3			$ 1
Scenario, Forecast
Income Tax Contingency [Line Items]
US corporate federal blended income tax rate					24.50%
Uncertain tax positions from decreases in positions taken in the next twelve months					$ 3
Legacy and Separation-related Expenses, net \| Ashland \| Tax Matters Agreement \| Ashland
Income Tax Contingency [Line Items]
Increase (decrease) in due to affiliates recognized in selling, general and administrative expense	(3)	$ 2	5	$ 2
Domestic Tax Authority
Income Tax Contingency [Line Items]
Increase in income tax resulting from U.S. tax reform legislation			66
KENTUCKY
Income Tax Contingency [Line Items]
Income tax expense	3		3
State income tax expense, related to change in state corporate tax rate	7
KENTUCKY \| Ashland \| Tax Matters Agreement \| Ashland
Income Tax Contingency [Line Items]
Income tax expense	4		4
Increase (decrease) in due to affiliates recognized in selling, general and administrative expense	4		4
KENTUCKY \| Legacy and Separation-related Expenses, net \| Ashland \| Tax Matters Agreement \| Ashland
Income Tax Contingency [Line Items]
Increase (decrease) in due to affiliates recognized in selling, general and administrative expense	$ 4		$ 1