Leases - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lessor, Sales-type Lease, Term of Contract		5 years
Lease contract modification-related charge	$ 741	$ 741	$ 0
Property, Plant and Equipment, Net	4,410	4,410		$ 3,901
Dispensing Lease Term Modification [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Capital Leases, Net Investment in Sales Type Leases	1,057	1,057
Property, Plant and Equipment, Net	$ 316	$ 316