Stockholders' Equity - Effect of VE Territory Covered Losses Through Conversion Rate Adjustments (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Conversion of Stock [Line Items]
Recovery through conversion rate adjustment	$ 0	$ (2)	$ 0	$ (2)
Series B preferred stock
Conversion of Stock [Line Items]
Reduction in equivalent number of as-converted shares of class A common stock (in shares)			1	0
Effective price per share (in dollars per share)			$ 203.08	$ 220.84
Recovery through conversion rate adjustment			$ 135	$ 35
Series C preferred stock
Conversion of Stock [Line Items]
Reduction in equivalent number of as-converted shares of class A common stock (in shares)			0	0
Effective price per share (in dollars per share)			$ 202.55	$ 220.71
Recovery through conversion rate adjustment			$ 6	$ 20