Discontinued Operations - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Discontinued Operations And Disposal Groups [Abstract]
Income (loss) from discontinued operations, net of tax	$ 1	$ (1)	$ 1	$ (2)