PROPERTY, PLANT AND EQUIPMENT AND OPERATING LEASE RIGHT-OF-USE ASSETS - Property, Plant and Equipment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Original cost	$ 86,037		$ 85,476
Less accumulated depreciation and amortization	(35,773)		(35,637)
Property, plant and equipment – net	50,265		$ 49,839
Consolidated depreciation and amortization on property, plant and equipment	1,249	$ 1,272
Operating lease income	1,139	1,182
Fixed lease income	776	823
Variable lease income	$ 363	$ 359