Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Sep. 30, 2025
Income Tax Disclosure [Abstract]
Effective income tax rate	13.20%	14.30%	15.30%	15.80%
Gross unrecognized tax benefits	$ 21		$ 21		$ 29
Accrued interest and penalties related to unrecognized tax benefits	2		2		$ 2
Reasonably possible amount of reduction in gross unrecognized tax benefits for the next twelve months	14		14
Reasonably possible amount of net reduction to income tax provision if unrecognized tax benefits were recognized	$ 14		$ 14