Summary of Significant Accounting Policies (Details) $ in Millions		3 Months Ended		9 Months Ended
		Jun. 30, 2016 USD ($) country	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) country	Jun. 30, 2015 USD ($)	Jun. 21, 2016
Business Acquisition [Line Items]
Number of countries in which entity operates (more than) | country		200		200
Foreign currency translation adjustments		$ (404)	$ 0	$ (404)	$ 1
Visa Europe
Business Acquisition [Line Items]
Share capital of Visa Europe acquired (percent)						100.00%
Deferred cash consideration liability	[1]	$ 1,236		$ 1,236

[1] the fair value of deferred cash consideration of €1.0 billion, plus 4% compound annual interest, payable on the third anniversary of the Closing, discounted at a rate of 1.2%.