Income Taxes - Additional Information (Details) $ in Millions	9 Months Ended
	Jun. 30, 2019 USD ($)
Income Tax Disclosure [Abstract]
Other tax expense (benefit)	$ 10
Other tax expense benefit related to historic unremitted foreign earnings	(67)
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	$ 2