Fair Value Measures (Fair Value, Other Disclosures) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Sep. 30, 2014	Oct. 03, 2012	Oct. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Related Parties, Stated Interest Rate Percentage				1.65%
Unified Communications Solutions Provider
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Related Parties, Noncurrent			$ 10
Unified Communications Solutions Provider | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Related Parties, Noncurrent	$ 9	$ 9
Unified Communications Solutions Provider | Advance to Parent due October 3, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Related Parties, Stated Interest Rate Percentage			1.85%
Other Assets
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Related Parties, Noncurrent				$ 8
Other Assets | Estimate of Fair Value Measurement
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Receivable, Related Parties, Noncurrent	$ 7	$ 6