Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Income Tax [Line Items]
Deferred tax assets, net of valuation allowance, current	$ 387	$ 355
Deferred tax assets, net of valuation allowance, noncurrent	142	100
Deferred tax liabilities, net, current	5	10
Deferred tax liabilities, net, noncurrent	1,951	130
Undistributed earnings of foreign subsidiaries	7,500
Accrued unrecognized tax benefits interest and penalties	84	10	$ 8
Unrecognized tax benefits interest and penalties reflected in current year	8	2	2
Tax reductions related to tax holidays	102	108	95
Income taxes paid, net	240	$ 330	$ 454
Deferred Income Taxes and Other
Income Tax [Line Items]
Indemnification liability, non-current	$ 217