CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Millions	Sep. 30, 2018		Sep. 30, 2017
Series A convertible participating preferred stock
Preferred stock, shares issued	0		0
Series B convertible participating preferred stock
Preferred stock, shares issued	2		2
Preferred stock, shares outstanding	2		2
Series C convertible participating preferred stock
Preferred stock, shares issued	3		3
Preferred stock, shares outstanding	3		3
Class A common stock
Common stock, par value	$ 0.0001		$ 0.0001
Common stock, shares authorized	2,001,622		2,001,622
Common stock, shares, issued	1,768		1,818
Common stock, shares, outstanding	1,768	[1]	1,818
Class B common stock
Common stock, par value	$ 0.0001		$ 0.0001
Common stock, shares authorized	622		622
Common stock, shares, issued	245		245
Common stock, shares, outstanding	245		245
Class C common stock
Common stock, par value	$ 0.0001		$ 0.0001
Common stock, shares authorized	1,097		1,097
Common stock, shares, issued	12		13
Common stock, shares, outstanding	12		13
Preferred Stock
Preferred stock, par value	$ 0.0001		$ 0.0001
Preferred stock, shares authorized	25		25
Preferred stock, shares issued	5		5

[1] Class A common stock shares outstanding reflect repurchases settled on or before September 30, 2018.