Accrued Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Other Liabilities Disclosure [Abstract]
Accrued operating expenses	$ 434	$ 347
Accrued interest expenses	149	145
Accrued income taxes-(See Note 18-Income Taxes)	243	153
Other	303	483
Total	$ 1,129	$ 1,128