Number of shares of equity interests issued or issuable to acquire entity.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

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Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Business Acquisition, Preferred Stock, Conversion Ratio

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Debt Instruments, Number of Convertible Debt Instruments Issued

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Visa Europe - Additional Information (Detail) $ / shares in Units, $ in Millions, € in Billions						12 Months Ended
	Jun. 21, 2016 EUR (€) shares	Jun. 21, 2016 EUR (€)	Jun. 21, 2016 EUR (€) debt_instrument	Jun. 21, 2016 EUR (€)	Jun. 21, 2016 USD ($)	Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2016 USD ($) $ / shares	Sep. 30, 2015 USD ($)	Jun. 21, 2016 USD ($) $ / shares
Class of Stock [Line Items]
Convertible participating preferred stock issued in Visa Europe acquisition \| $						$ 0	$ 5,717	$ 0
Average price of common stock (USD per share)									$ 77.33
Visa Europe
Class of Stock [Line Items]
Share capital of Visa Europe acquired (percent)	100.00%	100.00%	100.00%	100.00%					100.00%
Up-front cash consideration		€ 12.2			$ 13,900
Convertible participating preferred stock issued in Visa Europe acquisition		5.3			$ 6,100
Contingent consideration \| €	€ 1.0	€ 1.0	€ 1.0	€ 1.0
Accrued interest on contingent consideration	4.00%	4.00%	4.00%	4.00%					4.00%
Number of convertible debt instruments issued			3	3
Initial conversion rate of UK&I and Europe preferred stock into class A common or class A equivalent preferred stock	13.952	13.952	13.952	13.952					13.952
Total purchase consideration \| $									$ 18,784
Visa Europe \| Class A equivalent preferred stock
Class of Stock [Line Items]
Preferred stock, par value									$ 0.0001
Visa Europe \| U.K.&I preferred stock
Class of Stock [Line Items]
Shares issued at closing (shares) \| shares	2,480,466
Preferred stock, par value									0.0001
Visa Europe \| Europe preferred stock
Class of Stock [Line Items]
Shares issued at closing (shares) \| shares	3,156,823
Preferred stock, par value									$ 0.0001
Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value						$ 0.0001	$ 0.0001
Preferred Stock \| Visa Europe
Class of Stock [Line Items]
Shares issued at closing (shares) \| shares	79,000,000