CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares shares in Millions	Mar. 31, 2021	Sep. 30, 2020
Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	25	25
Preferred stock, shares issued (in shares)	5	5
Preferred stock, shares outstanding (in shares)	5	5
Series A preferred stock
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Series B preferred stock
Preferred stock, shares issued (in shares)	2	2
Preferred stock, shares outstanding (in shares)	2	2
Series C preferred stock
Preferred stock, shares issued (in shares)	3	3
Preferred stock, shares outstanding (in shares)	3	3
Class A common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	2,001,622	2,001,622
Common stock, shares issued (in shares)	1,694	1,683
Common stock, shares outstanding (in shares)	1,694	1,683
Class B common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	622	622
Common stock, shares issued (in shares)	245	245
Common stock, shares outstanding (in shares)	245	245
Class C common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	1,097	1,097
Common stock, shares issued (in shares)	11	11
Common stock, shares outstanding (in shares)	11	11