Fair Value Measures (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - Recurring - USD ($) $ in Millions	Jun. 30, 2015	Sep. 30, 2014
Other assets, non-current | Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	$ 1	$ 1
Foreign currency forward contracts | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure	1
Foreign currency forward contracts | Other current assets | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	1
Foreign currency forward contracts | Other current liabilities | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure		2
Quoted prices in active markets for identical instruments (Level 1) | Other assets, non-current | Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	1	1
Quoted prices in active markets for identical instruments (Level 1) | Foreign currency forward contracts | Other current assets | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0
Quoted prices in active markets for identical instruments (Level 1) | Foreign currency forward contracts | Other current liabilities | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure	0	0
Significant other observable inputs (Level 2) | Other assets, non-current | Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Significant other observable inputs (Level 2) | Foreign currency forward contracts | Other current assets | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	1
Significant other observable inputs (Level 2) | Foreign currency forward contracts | Other current liabilities | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure	1	2
Significant unobservable inputs (Level 3) | Other assets, non-current | Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0	0
Significant unobservable inputs (Level 3) | Foreign currency forward contracts | Other current assets | Derivative assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure	0
Significant unobservable inputs (Level 3) | Foreign currency forward contracts | Other current liabilities | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities, Fair Value Disclosure	$ 0	$ 0