Stockholders' Equity - Additional Information (Detail) $ / shares in Units, $ in Millions								12 Months Ended
		Sep. 30, 2017 USD ($) conversion_rate shares		Sep. 30, 2016 shares	Jun. 21, 2016 debt_instrument	Jun. 21, 2016	Mar. 19, 2015 conversion_rate	Sep. 30, 2017 USD ($) conversion_rate $ / shares shares	Sep. 30, 2016 USD ($) shares	Oct. 31, 2017 $ / shares	Apr. 20, 2017 USD ($)
Class of Stock [Line Items]
Reduction in as-converted stock (in shares) | shares								79,000,000
Reduction in as-converted stock (in dollars per share) | $ / shares								$ 89.92
Stock repurchase program, authorized amount											$ 5,000
Stock repurchase plan, remaining authorized funds		$ 3,900						$ 3,900
Dividends, paid								$ 1,600
Dividends, paid per share | $ / shares								$ 0.165
Subsequent Event
Class of Stock [Line Items]
Dividends, per share amount declared | $ / shares										$ 0.195
Deposit into Litigation Escrow
Class of Stock [Line Items]
Deposits into litigation escrow account								$ 0	$ 0
Class A common stock
Class of Stock [Line Items]
Common stock split, conversion ratio							4
Stockholders' Equity Note, Stock Split, Dividend Ratio							3
Shares repurchased in the open market (in shares) | shares	[1],[2]							77,000,000	91,000,000
Class B common stock
Class of Stock [Line Items]
Common stock, conversion rate | conversion_rate	[3]	1.6483					1.6483	1.6483
Class C common stock
Class of Stock [Line Items]
Common stock, conversion rate | conversion_rate		4.0000					4.0	4.0000
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, conversion rate		13.0770	[3]	13.952
Recovery through conversion rate adjustment								$ 190
Preferred stock, shares outstanding | shares		2,000,000		2,000,000				2,000,000	2,000,000
Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares outstanding | shares		5,000,000		5,000,000				5,000,000	5,000,000
Accelerated Share Repurchase Program Aggregate | Class C common stock
Class of Stock [Line Items]
Shares of class C common stock released from transfer restrictions, converted to class A common stock | shares								139,000,000
Preferred Stock
Class of Stock [Line Items]
Recovery through conversion rate adjustment								$ (191)
Preferred Stock | Series B Preferred Stock
Class of Stock [Line Items]
Recovery through conversion rate adjustment								$ (190)
Visa Europe
Class of Stock [Line Items]
Number of convertible debt instruments issued					3	3
Visa Europe | Class A equivalent preferred stock
Class of Stock [Line Items]
Preferred stock, conversion rate								100

[1] All shares repurchased in the open market have been retired and constitute authorized but unissued shares.

[2] Shares repurchased in the open market reflect repurchases settled during fiscal 2017. These amounts include repurchases traded but not yet settled on or before September 30, 2016 for fiscal 2017 or September 30, 2015 for fiscal 2016 and exclude repurchases traded but not yet settled on or before September 30, 2017 for fiscal 2017 or September 30, 2016 for fiscal 2016.

[3] The class B to class A common stock conversion rate is presented on a rounded basis. Conversion calculations for dividend payments are based on a conversion rate rounded to the tenth decimal.