v3.24.0.1
Fair Value - Fair Value Hierarchy (Details) - USD ($)
$ in Millions
Dec. 31, 2023
Dec. 31, 2022
Assets    
Available-for-sale investment securities $ 330 $ 337
Fair Value, Recurring    
Assets    
Cash equivalents 724 665
Available-for-sale investment securities 330 337
Equity investment securities   8
Aircraft fuel derivatives 4 3
Fair Value, Recurring | Level 1    
Assets    
Cash equivalents 724 665
Available-for-sale investment securities 0 0
Equity investment securities 0 8
Aircraft fuel derivatives 0 0
Fair Value, Recurring | Level 2    
Assets    
Cash equivalents 0 0
Available-for-sale investment securities 314 324
Equity investment securities   0
Aircraft fuel derivatives 4 3
Fair Value, Recurring | Level 3    
Assets    
Cash equivalents 0 0
Available-for-sale investment securities 16 13
Equity investment securities   0
Aircraft fuel derivatives $ 0 $ 0