Leases - Schedule of Contractual Future Lease Obligations (Detail) $ in Millions	Sep. 30, 2019 USD ($)
Contractual Obligation, Fiscal Year Maturity Schedule [Abstract]
Operating leases, One year or Less	$ 305
Operating leases, Over One Through Two Years	255
Operating leases, Over Two Through Three Years	230
Operating leases, Over Three Through Four Years	186
Operating leases, Over Four Through Five Years	138
Operating leases, Thereafter	416
Operating leases	1,530
Operating leases, amounts representing interest	(186)
Operating leases, lease liabilities	1,344
Finance leases, One Year or Less	17
Finance leases, Over One Through Two Years	15
Finance leases, Over Two Through Three Years	13
Finance leases, Over Three Through Four Years	11
Finance leases, Over Four Through Five Years	10
Finance leases, thereafter	37
Finance leases	103
Finance leases, Amounts representing interest	(32)
Finance leases, lease liabilities	$ 71