Stockholders' Equity - Schedule of As-Converted Class B Common Stock (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Stockholders' Equity Note [Abstract]
Reduction in equivalent number of as-converted shares of class A common stock (in shares)	4
Effective price per share (in dollars per share)	$ 205.06
Deposits under the U.S. retrospective responsibility plan	$ 850	$ 0