Fair Value Measurements and Investments (Tables)

9 Months Ended

Jun. 30, 2019

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
	June 30, 2019		September 30, 2018		June 30, 2019		September 30, 2018
	(in millions)
Assets
Cash equivalents and restricted cash equivalents:
Money market funds	$	6,275	$	6,252
U.S. government-sponsored debt securities					$	50	$	1,048
Investment securities:
Marketable equity securities	125		113
U.S. government-sponsored debt securities					5,484		5,008
U.S. Treasury securities	574		2,508
Other current and non-current assets:
Derivative instruments					211		78
Total	$	6,974	$	8,873	$	5,745	$	6,134
Liabilities
Accrued and other liabilities:
Derivative instruments					$	74	$	22
Total	$	—	$	—	$	74	$	22