Fair Value of Intangible Assets and Related Accumulated Amortization Expense (Detail) - USD ($) $ in Millions |
Sep. 30, 2015 |
Sep. 30, 2014 |
|---|---|---|
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross | $ 691 | $ 678 |
| Accumulated Amortization | (339) | (276) |
| Finite-Lived Intangible Assets, Net | 352 | 402 |
| Indefinite-lived Intangible Assets | 11,009 | 11,009 |
| Net | 11,361 | 11,411 |
| Customer relationships | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross | 351 | 339 |
| Accumulated Amortization | (196) | (162) |
| Finite-Lived Intangible Assets, Net | 155 | 177 |
| Tradenames | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross | 192 | 192 |
| Accumulated Amortization | (67) | (54) |
| Finite-Lived Intangible Assets, Net | 125 | 138 |
| Reseller relationships | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross | 95 | 95 |
| Accumulated Amortization | (59) | (48) |
| Finite-Lived Intangible Assets, Net | 36 | 47 |
| Other Intangible Assets | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Gross | 53 | 52 |
| Accumulated Amortization | (17) | (12) |
| Finite-Lived Intangible Assets, Net | $ 36 | $ 40 |