SEGMENTS - Segment Reporting (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information, Profit (Loss)
Operating revenue	$ 58,048	$ 50,582	$ 29,899
Depreciation and amortization	2,341	2,107	1,998
Operating income (loss)	5,521	3,661	1,886
Interest expense, net	834	1,029	1,279
Total assets, end of period	73,644	72,288	72,459
Capital expenditures	5,323	6,366	3,247
Operating Segments | Airline
Segment Reporting Information, Profit (Loss)
Operating revenue	54,669	45,605	26,670
Depreciation and amortization	2,341	2,107	1,998
Operating income (loss)	5,136	2,884	1,888
Interest expense, net	834	1,029	1,279
Total assets, end of period	71,529	69,355	70,417
Capital expenditures	5,088	6,217	3,188
Operating Segments | Refinery
Segment Reporting Information, Profit (Loss)
Operating revenue	7,572	10,706	6,054
Depreciation and amortization	94	93	95
Operating income (loss)	385	777	(2)
Interest expense, net	17	12	7
Total assets, end of period	2,174	3,039	2,099
Capital expenditures	235	149	59
Intersegment Sales/Other
Segment Reporting Information, Profit (Loss)
Operating revenue	(4,193)	(5,729)	(2,825)
Depreciation and amortization	(94)	(93)	(95)
Interest expense, net	(17)	(12)	(7)
Total assets, end of period	(59)	(106)	(57)
Intersegment Sales/Other | Sales to airline segment
Segment Reporting Information, Profit (Loss)
Operating revenue	(1,535)	(1,976)	(492)
Intersegment Sales/Other | Exchanged products
Segment Reporting Information, Profit (Loss)
Operating revenue	(2,354)	(3,475)	(2,293)
Intersegment Sales/Other | Sales of refined products
Segment Reporting Information, Profit (Loss)
Operating revenue	$ (304)	$ (278)	$ (40)