The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets.

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Summary of Significant Accounting Policies - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Depreciation	$ 91	$ 71	$ 50
Intangible amortization	0	1	0
Total depreciation and amortization	91	72	$ 50
Property and equipment, net	$ 510	376
Aircraft and spare engines
Property, Plant and Equipment [Line Items]
Useful life	25 years
Residual Value	10.00%
Flight equipment leasehold improvements
Property, Plant and Equipment [Line Items]
Residual Value	0.00%
Aircraft rotable parts
Property, Plant and Equipment [Line Items]
Residual Value	10.00%
Ground property and equipment
Property, Plant and Equipment [Line Items]
Residual Value	0.00%
Ground property and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Ground property and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Ground equipment leasehold improvements
Property, Plant and Equipment [Line Items]
Residual Value	0.00%
Ground equipment leasehold improvements \| Maximum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Internal-use software
Property, Plant and Equipment [Line Items]
Residual Value	0.00%
Property and equipment, net	$ 23	18
Internal-use software \| Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Internal-use software \| Maximum
Property, Plant and Equipment [Line Items]
Useful life	10 years
Capitalized maintenance
Property, Plant and Equipment [Line Items]
Residual Value	0.00%
Property and equipment, net	$ 225	$ 126
Buildings
Property, Plant and Equipment [Line Items]
Residual Value	10.00%
Buildings \| Maximum
Property, Plant and Equipment [Line Items]
Useful life	40 years