Segment Information - Schedule of Selected Financial Information by Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Selected Information [Line Items]
Operating Revenues and Other	$ 6,025	$ 5,573	$ 12,148	$ 11,617
Operating Income (Loss)	2,130	1,970	4,401	4,542
Other Income, Net	66	51	128	116
Interest Expense, Net	(36)	(35)	(69)	(77)
Income Before Income Taxes	2,160	1,986	4,460	4,581
Operating Segments
Selected Information [Line Items]
Operating Revenues and Other	6,025	5,573	12,148	11,617
Operating Income (Loss)	2,130	1,970	4,401	4,542
Segment Reconciling Items
Selected Information [Line Items]
Other Income, Net	66	51	128	116
Interest Expense, Net	(36)	(35)	(69)	(77)
United States | Operating Segments
Selected Information [Line Items]
Operating Revenues and Other	5,956	5,520	12,016	11,461
Operating Income (Loss)	2,147	1,961	4,411	4,473
Trinidad | Operating Segments
Selected Information [Line Items]
Operating Revenues and Other	69	52	132	155
Operating Income (Loss)	16	16	32	82
Other International | Operating Segments
Selected Information [Line Items]
Operating Revenues and Other	0	1	0	1
Operating Income (Loss)	$ (33)	$ (7)	$ (42)	$ (13)