Intangible Assets and Goodwill	6 Months Ended
Intangible Assets and Goodwill	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	Note 5—Intangible Assets and Goodwill Goodwill and intangible assets at March 31, 2017 decreased from September 30, 2016 primarily due to measurement period adjustments as the Company updated the purchase price allocation during the second quarter of fiscal 2017. See Note 2—Visa Europe. Goodwill and intangible assets also decreased due to foreign currency translation, which is recorded as a component of accumulated other comprehensive loss in the consolidated balance sheet. In February 2017, the Company acquired a business for a total purchase consideration net of cash received of approximately $302 million, paid primarily with cash on hand. Total purchase consideration has been allocated to the tangible and identifiable intangible assets acquired, and to liabilities assumed based on their respective fair values on the acquisition date. Related finite-lived intangible assets recorded totaled $104 million with a weighted-average useful life of eight years. Goodwill of $181 million was recorded to reflect the excess purchase consideration over net assets acquired. The consolidated financial statements include the operating results of the acquired business from the date of acquisition. Pro forma information related to the acquisition has not been presented as the impact is not material to the Company's financial results.

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.