U.S. and Europe Retrospective Responsibility Plans - Preferred Stock (Details) $ / shares in Units, shares in Millions, $ in Millions		6 Months Ended			12 Months Ended
		Mar. 31, 2019 USD ($) $ / shares shares		Mar. 31, 2018 USD ($)	Sep. 30, 2018 USD ($) $ / shares shares
Class of Stock [Line Items]
Recovery Through Conversion Rate Adjustment		$ 0		$ 0
As-converted value of preferred stock	[1]	11,860	[2]		$ 11,403	[3]
Book Value of Preferred stock	[1]	5,464			5,470
Right to recover for covered losses	[1]	(163)			(7)
Total recovery for covered losses available, as converted	[1]	11,697			11,396
Total recovery for covered losses available, book value	[1]	$ 5,301			$ 5,463
Share Price | $ / shares		$ 156.19			$ 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]	5,013	[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]	6,847	[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		$ 50

[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 March 31, 2019; (b) 12.939 and 13.886, the class A common stock conversion rate applicable to the UK&I and Europe preferred stock as of March 31, 2019, respectively; and (c) $156.19, Visa’s class A common stock closing stock price as of March 31, 2019.

[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.