Income Taxes - Provision (Benefit) for Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
U.S. federal and state, Current									$ (4)	$ (3)	$ (1)
U.S. federal and state, Deferred									(4)	(6)	(8)
U.S. federal and state, Total									(8)	(9)	(9)
Foreign, Current									86	70	62
Foreign, Deferred									14	(1)	2
Foreign, Total									100	69	64
Total U.S and foreign	$ 41	$ 20	$ 7	$ 24	$ 8	$ 16	$ 16	$ 20	$ 92	$ 60	$ 55