LEASES (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Jan. 01, 2019
Lessor, Operating Lease, Lease Not yet Commenced, Assumption and Judgment, Value of Underlying Asset, Amount	$ 90	$ 90
Operating Lease, Expense	139	264
Finance Lease, Right-of-Use Asset, Amortization	11	17
Finance Lease, Interest Expense	7	13
Finance Lease, Cost	18	30
Short-term Lease, Cost	50	100
Variable Lease, Cost	63	107
Sublease Income	(1)	(2)
Lease, Cost	269	499
Operating Lease, Payments		269
Finance Lease, Interest Payment on Liability		13
Finance Lease, Principal Payments		9
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		2,385
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability		60
Operating Lease, Right-of-Use Asset	2,183	2,183	$ 0
Property, Plant and Equipment, Gross	54,937	54,937	53,984
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(33,687)	(33,687)	(32,566)
Total Lease Assets	2,504	2,504
Operating Lease, Liability, Current	421	421	0
Finance Lease, Liability, Current	35	35
Operating Lease, Liability, Noncurrent	1,779	1,779	0
Finance Lease, Liability, Noncurrent	364	364
Total Lease Liabilities	$ 2,599	$ 2,599
Operating Lease, Weighted Average Remaining Lease Term	8 years 2 months	8 years 2 months
Finance Lease, Weighted Average Remaining Lease Term	11 years 8 months	11 years 8 months
Operating Lease, Weighted Average Discount Rate, Percent	4.21%	4.21%
Finance Lease, Weighted Average Discount Rate, Percent	6.72%	6.72%
Lessee, Operating Lease, Liability, Payments, Due 2019	$ 291	$ 291	366
Finance Lease, Liability, Payments, Due 2019	40	40
Lessee, Operating Lease, Liability, Payments, Due 2020	510	510	329
Finance Lease, Liability, Payments, Due 2020	70	70
Lessee, Operating Lease, Liability, Payments, Due 2021	401	401	296
Finance Lease, Liability, Payments, Due 2021	69	69
Lessee, Operating Lease, Liability, Payments, Due 2022	346	346	269
Finance Lease, Liability, Payments, Due 2022	52	52
Lessee, Operating Lease, Liability, Payments, Due 2023	259	259	227
Finance Lease, Liability, Payments, Due 2023	79	79
Lessee, Operating Lease, Liability, Payments, Due 2024 and thereafter	979	979	855
Finance Lease, Liability, Payments, Due 2024 and thereafter	308	308
Lessee, Operating Lease, Liability, Payments, Due	2,786	2,786	$ 2,342
Finance Lease, Liability, Payments, Due	618	618
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	586	586
Finance Lease, Liability, Undiscounted Excess Amount	219	219
Operating Lease, Liability	2,200	2,200
Finance lease obligations 1	399	$ 399
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract		20 years
Residual Value Guarantees [Member]
Guarantee Obligations Year Of Final Expiration		2027	2028
Guarantor Obligations, Maximum Exposure, Undiscounted	755	$ 755	$ 885
Guarantor Obligations, Current Carrying Value	0	0	$ 130
Finance Leases [Member]
Property, Plant and Equipment, Gross	466	466
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ (145)	$ (145)
Accounting Standards Update 2016-02 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 2,300
Minimum [Member]
Lessee, Operating and Finance Leases, Remaining Lease Term		1 year
Maximum [Member]
Lessee, Operating and Finance Leases, Remaining Lease Term		50 years