Visa Europe (Details) $ / shares in Units, $ in Millions, € in Billions			9 Months Ended
	Jun. 21, 2016 EUR (€) shares	Jun. 21, 2016 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 21, 2016 EUR (€)
Class of Stock [Line Items]
Series B and C convertible participating preferred stock issued in Visa Europe acquisition (Note 2) | $			$ 0	$ 5,717
Additional cash consideration payable on the third anniversary of closing | $			$ 1,258		$ 1,225
Class A equivalent preferred stock
Class of Stock [Line Items]
Preferred stock, par value		$ 0.0001
U.K.& I preferred stock
Class of Stock [Line Items]
Preferred stock, par value		0.0001
Europe preferred stock
Class of Stock [Line Items]
Preferred stock, par value		$ 0.0001
Visa Europe
Class of Stock [Line Items]
Share capital of Visa Europe acquired (percent)						100.00%
Up-front cash consideration	€ 12.2	$ 13,900
Shares issued or issuable at closing (shares) | shares	79,000,000	79,000,000
Series B and C convertible participating preferred stock issued in Visa Europe acquisition (Note 2)	€ 5.3	$ 6,100
Additional cash consideration payable on the third anniversary of closing | €						€ 1.0
Compound annual interest rate on additional consideration paid on third anniversary of closing (percent)						4.00%
Initial conversion rate of U.K.&I and Europe preferred stock into Class A equivalent preferred stock						13.952
Visa Europe | Class A common stock
Class of Stock [Line Items]
Closing stock price (in USD per share)		$ 77.33
Visa Europe | U.K.& I preferred stock
Class of Stock [Line Items]
Shares issued or issuable at closing (shares) | shares	2,480,466	2,480,466
Visa Europe | Europe preferred stock
Class of Stock [Line Items]
Shares issued or issuable at closing (shares) | shares	3,156,823	3,156,823