Fair Value Measurements and Derivative Instruments - Schedule of Designated Cash Flow Hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Loss on Derivatives	$ (14)	$ (11)	$ 42	$ (42)
Interest rate swaps
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Loss on Derivatives	8	23	29	11
Foreign currency forward contracts
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Loss on Derivatives	(31)	(9)	(102)	13
Fuel swaps
Effect of derivative instruments involved in hedging on the consolidated financial statements
Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Loss on Derivatives	$ 9	$ (25)	$ 115	$ (66)