Debt and Other Financing Activities - U.S. Accounts Receivable Sales Program - Additional Information (Details) - U.S. Accounts Receivable Sales Program [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024	Sep. 30, 2024
Disclosure Of Sales Program Of Receivable [Line Items]
Loss on sale of receivables	$ 1	$ 1	$ 2	$ 2
Sales against the buyers limit			60		$ 71
Maximum limit of receivables can transfer			60		71
Amount transferred in accounts receivable			73		85
Gross cash proceeds received for accounts receivable transferred			189	174
Cash proceeds collected			200	159
Increase (decrease) in account receivable sales volume			11	$ 15
Maximum [Member]
Disclosure Of Sales Program Of Receivable [Line Items]
Recorded liabilities related to service obligations and limited guarantee	$ 1		$ 1		$ 1