Intangible Assets and Goodwill - Schedule of Changes in Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Goodwill [Roll Forward]
Balance as of beginning of period	$ 18,941	$ 17,997
Goodwill from acquisitions	794	790
Foreign currency translation	144	154
Balance as of end of period	$ 19,879	$ 18,941