Consolidated Statements of Financial Position (Paranthetical) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 14	$ 15
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized (in shares)	100,000,000
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Common stock, par value (in dollars per share)	$ 0.001
Common stock, shares authorized (in shares)	500,000,000
Common stock, shares issued (in shares)	93,620,714
Common stock, shares outstanding (in shares)	93,620,714