Fair Value Measurements and Investments (Tables)

9 Months Ended

Jun. 30, 2015

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis

Assets and Liabilities Measured at Fair Value on a Recurring Basis

	Fair Value Measurements Using Inputs Considered as
	Level 1				Level 2				Level 3
	June 30, 2015		September 30, 2014		June 30, 2015		September 30, 2014		June 30, 2015		September 30, 2014
	(in millions)
Assets
Cash equivalents and restricted cash:
Money market funds	$	2,239	$	2,277
Commercial paper					$	45	$	37
Investment securities, trading:
Equity securities	71		69
Investment securities, available-for-sale:
U.S. government-sponsored debt securities					2,482		2,162
U.S. Treasury securities	2,756		2,176
Equity securities	12		58
Corporate debt securities					548		522
Auction rate securities									$	7	$	7
Prepaid and other current assets:
Foreign exchange derivative instruments					71		40
Total	$	5,078	$	4,580	$	3,146	$	2,761	$	7	$	7
Liabilities
Accrued liabilities:
Visa Europe put option									$	255	$	145
Foreign exchange derivative instruments					$	8	$	6
Total	$	—	$	—	$	8	$	6	$	255	$	145