LEASES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Operating Lease, Cost	$ 123	$ 122	$ 362	$ 362
Finance Lease, Right-of-Use Asset, Amortization	19	16	53	42
Finance Lease, Interest Expense	6	7	19	19
Finance Lease, Cost	25	23	72	61
Short-term Lease, Cost	57	54	177	161
Variable Lease, Cost	78	45	228	157
Sublease Income	(2)	(2)	(5)	(4)
Lease, Cost	281	$ 242	834	737
Operating Lease, Payments			364	357
Finance Lease, Interest Payment on Liability			19	19
Finance Lease, Principal Payments			48	34
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			133	68
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability			73	$ 142
Operating lease right-of-use assets	1,727		1,727		$ 1,856
Property	56,522		56,522		56,325
Accumulated depreciation	(36,874)		(36,874)		(36,086)
Total Lease Assets	2,190		2,190		2,305
Operating lease liabilities - current	413		413		416
Finance Lease, Liability, Current	68		68		54
Operating lease liabilities - noncurrent	1,428		1,428		1,521
Finance Lease, Liability, Noncurrent	474		474		464
Total Lease Liabilities	$ 2,383		$ 2,383		$ 2,455
Operating Lease, Weighted Average Remaining Lease Term	7 years 2 months 12 days		7 years 2 months 12 days		7 years 7 months 6 days
Finance Lease, Weighted Average Remaining Lease Term	10 years 3 months 18 days		10 years 3 months 18 days		11 years 7 months 6 days
Operating Lease, Weighted Average Discount Rate, Percent	3.63%		3.63%		3.84%
Finance Lease, Weighted Average Discount Rate, Percent	5.04%		5.04%		5.41%
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year	$ 140		$ 140
Finance Lease, Liability, Payments, Remainder of Fiscal Year	29		29
Lessee, Operating Lease, Liability, to be Paid, Year One	434		434
Finance Lease, Liability, to be Paid, Year One	89		89
Lessee, Operating Lease, Liability, Payments, Due Year Two	351		351
Finance Lease, Liability, Payments, Due Year Two	113		113
Lessee, Operating Lease, Liability, Payments, Due Year Three	273		273
Finance Lease, Liability, Payments, Due Year Three	58		58
Lessee, Operating Lease, Liability, Payments, Due Year Four	201		201
Finance Lease, Liability, to be Paid, Year Four	47		47
Lessee, Operating Lease, Liability, Payments, Due Year Five	744		744
Finance Lease, Liability, Payments, Due Year Five	375		375
Lessee, Operating Lease, Liability, Payments, Due	2,143		2,143
Finance Lease, Liability, Payment, Due	711		711
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	302		302
Finance Lease, Liability, Undiscounted Excess Amount	169		169
Operating Lease, Liability	1,841		1,841
Finance lease obligations 2	542		542
Lessee, Additional Leases Not yet Commenced, Assumptions and Judgment, Amount	152		$ 152
Lessee, Additional Leases Not yet Commenced, Term of Contract			20 years
Residual Value Guarantees [Member]
Guarantor Obligations, Maximum Exposure, Undiscounted	805		$ 805		$ 818
Guarantor Obligations, Current Carrying Value	56		56		22
Finance Leases [Member]
Property	726		726		665
Accumulated depreciation	$ (263)		$ (263)		$ (216)