Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended						9 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2022	Jun. 30, 2021
Numerator
Net income	$ 99	$ 81	$ 87	$ 97	$ 68	$ 87	$ 267	$ 252
Denominator
Weighted-average common shares outstanding (shares)	179			182			180	183
Effect of potentially dilutive securities (shares)	1			1			1	1
Weighted average diluted shares outstanding (shares)	180			183			181	184
Earnings per share
Basic (usd per share)	$ 0.55			$ 0.53			$ 1.48	$ 1.38
Diluted (usd per share)	$ 0.55			$ 0.53			$ 1.47	$ 1.37