Debt and Other Obligations - Schedule of Long-Term Obligations (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Revolving Credit Facility Expiry August 2016 [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 750	$ 750
Debt instrument due, year	2016	2016
Chinese Renminbi Notes, Due Through 2016, 6.15%-6.77% [Member]
Debt Instrument [Line Items]
Debt instrument interest rate, minimum	6.15%	6.15%
Debt instrument interest rate, maximum	6.77%	6.77%
Debt instrument maturity, maximum range	2016	2016
5% Notes Due 2017 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	5.00%	5.00%
Debt instrument due, year	2017	2017
2.55% Notes Due 2018 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	2.55%	2.55%
Debt instrument due, year	2018	2018
3.7% Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	3.70%	3.70%
Debt instrument due, year	2022	2022
Notes Due 2019, 7.42% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	7.42%	7.42%
Debt instrument due, year	2019	2019
Notes Due 2022, 8.35% - 8.47% [Member]
Debt Instrument [Line Items]
Debt instrument interest rate, minimum	8.35%	8.35%
Debt instrument interest rate, maximum	8.47%	8.47%
Debt instrument due, year	2022	2022
Notes Due 2028, 6.57%-7.28% [Member]
Debt Instrument [Line Items]
Debt instrument interest rate, minimum	6.57%	6.57%
Debt instrument interest rate, maximum	7.28%	7.28%
Debt instrument due, year	2028	2028
Guarantee Of Employee Stock Option Plan Note 8.29% [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	8.29%	8.29%
Chinese Renminbi Notes, Due Through 2018, 4.63%-6.15% [Member]
Debt Instrument [Line Items]
Debt instrument interest rate, minimum	4.63%	4.63%
Debt instrument interest rate, maximum	6.15%	6.15%
Debt instrument due, year	2018	2018
Capital Lease Obligations, Due Through 2031 [Member]
Debt Instrument [Line Items]
Debt instrument maturity, maximum range	2031	2031