COMMITMENTS AND CONTINGENCIES - LESSOR INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessor, Lease, Description [Line Items]
Property, plant and equipment	$ 53,928	$ 49,329
Accumulated depreciation	(13,925)	(12,877)
Property, plant and equipment, net	40,003	36,452
2021	207
2022	202
2023	202
2024	202
2025	202
Thereafter	2,344
Total undiscounted cash flows	3,359
Fixed lease payments	195	200	$ 194
Variable lease payments	1	6	72
Total revenues from operating leases	196	206	266
Depreciation expense	1,646	1,551	1,470
Assets Leased to Others [Member]
Lessor, Lease, Description [Line Items]
Property, plant and equipment	1,092	1,038
Accumulated depreciation	(228)	(179)
Property, plant and equipment, net	864	859
Depreciation expense	$ 39	$ 38	$ 72