Leases - Contractual Future Lease Payments to be Received (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Sales-type and direct finance leases, One Year or Less	$ 4,463
Sales-type and direct finance leases, Over One Through Two Years	3,998
Sales-type and direct finance leases, Over Two Through Three Years	2,630
Sales-type and direct finance leases, Over Three Through Four Years	1,286
Sales-type and direct finance leases, Over Four Through Five Years	367
Sales-type and direct finance leases, thereafter	530
Sales-type and direct finance leases, lease payments	13,274
Sales-type and direct finance leases, amounts representing interest	(1,070)
Sales-type and direct finance leases, lease receivables	12,204	$ 12,207
Operating leases, One Year or Less	181
Operating leases, Over One Through Two Years	145
Operating leases, Over Two Through Three Years	103
Operating leases, Over Three Through Four Years	68
Operating leases, Over Four Through Five Years	48
Operating leases, thereafter	68
Operating leases, lease payments	$ 613