Additional Financial Information - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Supplemental Cash Flow Information [Line Items]
Accrued interest paid	$ 54,000,000	$ 56,000,000
Income taxes paid net of refunds	6,000,000
Tax refund	$ 0
GERMANY
Supplemental Cash Flow Information [Line Items]
Cash tax paid		8,000,000
Tax refund		$ 9,000,000