Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Sep. 30, 2012
Investment securities
Available-for-sale securities	$ 4,754		$ 3,960
Accrued liabilities
Visa Europe put option	145	[1]	145	[1]
Fair Value, Measurements, Recurring | Level 1
Prepaid and other current assets
Fair value, total assets	2,920		6,810
Accrued liabilities
Fair value, total liabilities	0		0
Fair Value, Measurements, Recurring | Level 1 | Money market funds
Cash equivalents and restricted cash
Cash equivalents and restricted cash	1,071		5,676
Fair Value, Measurements, Recurring | Level 1 | Equity securities
Investment securities
Trading securities	75		66
Available-for-sale securities	101		2
Fair Value, Measurements, Recurring | Level 1 | US Treasury securities
Investment securities
Available-for-sale securities	1,673		1,066
Fair Value, Measurements, Recurring | Level 2
Prepaid and other current assets
Fair value, total assets	3,047		2,990
Accrued liabilities
Fair value, total liabilities	15		11
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange derivative instruments
Accrued liabilities
Foreign exchange derivative instruments	15		11
Fair Value, Measurements, Recurring | Level 2 | Commercial Paper
Cash equivalents and restricted cash
Cash equivalents and restricted cash	51		93
Fair Value, Measurements, Recurring | Level 2 | U.S. government-sponsored agency debt securities
Investment securities
Available-for-sale securities	2,704		2,821
Fair Value, Measurements, Recurring | Level 2 | Corporate debt securities
Investment securities
Available-for-sale securities	269		63
Fair Value, Measurements, Recurring | Level 2 | Foreign exchange derivative instruments
Prepaid and other current assets
Foreign exchange derivative instruments	23		13
Fair Value, Measurements, Recurring | Level 3
Prepaid and other current assets
Fair value, total assets	7		7
Accrued liabilities
Fair value, total liabilities	145		157
Fair Value, Measurements, Recurring | Level 3 | Visa Europe put option
Accrued liabilities
Visa Europe put option			145
Fair Value, Measurements, Recurring | Level 3 | Earn out related to PlaySpan acquisition
Accrued liabilities
Visa Europe put option	0		12
Fair Value, Measurements, Recurring | Level 3 | Auction Rate Securities
Investment securities
Available-for-sale securities	$ 7		$ 7

[1] The put option is exercisable at any time at the sole discretion of Visa Europe with payment required 285 days thereafter. Classification in current liabilities is not an indication of management’s expectation of exercise and simply reflects the fact that the obligation resulting from the exercise of the instrument could become payable within 12 months.