U.S. and Europe Retrospective Responsibility Plans - Preferred Stock (Details) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		12 Months Ended
		Dec. 31, 2018 USD ($) $ / shares shares		Sep. 30, 2018 USD ($) $ / shares shares
Class of Stock [Line Items]
Recovery Through Conversion Rate Adjustment		$ 0
As-converted value of preferred stock	[1]	10,019	[2]	$ 11,403	[3]
Book Value of Preferred stock	[1]	5,464		5,470
Right to recover for covered losses	[1]	(92)		(7)
Total recovery for covered losses available, as converted	[1]	9,927		11,396
Total recovery for covered losses available, book value	[1]	$ 5,372		$ 5,463
Share Price | $ / shares		$ 131.94		$ 150.09
U.K.& I preferred stock
Class of Stock [Line Items]
Recovery Through Conversion Rate Adjustment		$ (5)		$ (35)
As-converted value of preferred stock	[1]	4,235	[2]	4,823	[3]
Book Value of Preferred stock	[1]	$ 2,286		$ 2,291
Preferred stock, shares outstanding | shares	[4]	2		2
Preferred stock, conversion ratio		12.9390		12.9550
Europe preferred stock
Class of Stock [Line Items]
Recovery Through Conversion Rate Adjustment		$ (1)		$ (21)
As-converted value of preferred stock	[1]	5,784	[2]	6,580	[3]
Book Value of Preferred stock	[1]	$ 3,178		$ 3,179
Preferred stock, shares outstanding | shares	[4]	3		3
Preferred stock, conversion ratio		13.8860		13.8880
Preferred Stock
Class of Stock [Line Items]
Recovery Through Conversion Rate Adjustment		$ 6

[1] Figures in the table may not recalculate exactly due to rounding. As-converted and book values are based on unrounded numbers.

[2] The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of December 31, 2018; (b)12.939 and 13.886, the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of December 31, 2018, respectively; and (c) $131.94, Visa’s class A common stock closing stock price as of December 31, 2018.

[3] The as-converted value of preferred stock is calculated as the product of: (a) 2 million and 3 million shares of the UK&I and Europe preferred stock outstanding, respectively, as of September 30, 2018; (b)12.955 and 13.888, the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of September 30, 2018, respectively; and (c) $150.09, Visa’s class A common stock closing stock price as of September 30, 2018.

[4] Figures in the table may not recalculate exactly due to rounding.