Income Taxes - Schedule of Income Tax Expense and Effective Tax Rate (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income tax expense	$ 31	$ 19	$ 83	$ 68
Effective tax rate percentage	24.20%	24.40%	24.80%	25.90%