Financial Instruments and Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Sep. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Remaining cash equivalents	$ 1,283,000,000		$ 1,283,000,000			$ 1,277,000,000
Fair value of long-term debt	11,400,000,000		11,400,000,000			11,600,000,000
Fair value of debt reclassified from long term to short term	802,000,000		802,000,000			750,000,000
Transfer of assets in and out of level 1, 2 and 3 measurements during the period	0	$ 0	0	$ 0
Transfer of liabilities in and out of level 1, 2 and 3 measurements during the period	0	$ 0	0	$ 0
Contingent consideration arrangements, decrease in contingent liability			26,000,000
Notes Due 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt					$ 500,000,000
Debt instrument, interest rate					1.75%
Notes1.450% due May 15, 2017 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt	$ 300,000,000		$ 300,000,000
Debt instrument, interest rate	1.45%		1.45%
Notes Due June 2016 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt						$ 750,000,000
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity period of short-term investments at the time of purchase			3 months
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Maturity period of short-term investments at the time of purchase			1 year