Revenue Recognition - Operating Revenues by Principal Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 967	$ 909	$ 1,815	$ 1,514
Domestic
Disaggregation of Revenue [Line Items]
Total operating revenues	877	819	1,658	1,365
Latin America
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 90	$ 90	$ 157	$ 149