Commitments and Contingencies (Detail)	3 Months Ended
	Dec. 31, 2018 USD ($) claim
Other Commitments [Line Items]
Number of pending claims | claim	0
Indemnification of officers and directors
Other Commitments [Line Items]
Liabilities under guarantor agreements	$ 0
General indemnification
Other Commitments [Line Items]
Liabilities under guarantor agreements	0
Indemnification of business partners
Other Commitments [Line Items]
Liabilities under guarantor agreements	0
Capital expenditures
Other Commitments [Line Items]
Purchase commitments	700,000,000
Lease commitment	$ 262,200,000
Capital expenditures | Minimum
Other Commitments [Line Items]
Lease, term of contract	5 years
Capital expenditures | Maximum
Other Commitments [Line Items]
Lease, term of contract	30 years
Miscellaneous purchase commitments
Other Commitments [Line Items]
Purchase commitments	$ 800,000,000