v3.26.1
FAIR VALUE MEASUREMENTS - Financial Assets and Liabilities Carried at Fair Value (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Recurring Basis | Money market fund investments and certificates of deposit | Cash Equivalents and Restricted Cash Equivalents    
ASSETS:    
Assets at fair value $ 15,603 $ 15,316
Recurring Basis | Equity securities with readily determinable fair values    
ASSETS:    
Assets at fair value 296 428
Recurring Basis | Not Designated as Hedging Instrument | Foreign currency exchange derivatives    
ASSETS:    
Assets at fair value 44 47
LIABILITIES:    
Liabilities at fair value 54 40
Nonrecurring Basis | Equity securities of private entities    
ASSETS:    
Assets at fair value 11 43
Nonrecurring Basis | Long-lived assets | KAYAK    
ASSETS:    
Assets at fair value [1]   179
Nonrecurring Basis | Goodwill | KAYAK    
ASSETS:    
Assets at fair value [1]   203
Level 1 | Recurring Basis | Money market fund investments and certificates of deposit | Cash Equivalents and Restricted Cash Equivalents    
ASSETS:    
Assets at fair value 15,603 15,316
Level 1 | Recurring Basis | Equity securities with readily determinable fair values    
ASSETS:    
Assets at fair value 296 428
Level 1 | Recurring Basis | Not Designated as Hedging Instrument | Foreign currency exchange derivatives    
ASSETS:    
Assets at fair value 0 0
LIABILITIES:    
Liabilities at fair value 0 0
Level 1 | Nonrecurring Basis | Equity securities of private entities    
ASSETS:    
Assets at fair value 0 0
Level 1 | Nonrecurring Basis | Long-lived assets | KAYAK    
ASSETS:    
Assets at fair value   0
Level 1 | Nonrecurring Basis | Goodwill | KAYAK    
ASSETS:    
Assets at fair value   0
Level 2 | Recurring Basis | Money market fund investments and certificates of deposit | Cash Equivalents and Restricted Cash Equivalents    
ASSETS:    
Assets at fair value 0 0
Level 2 | Recurring Basis | Equity securities with readily determinable fair values    
ASSETS:    
Assets at fair value 0 0
Level 2 | Recurring Basis | Not Designated as Hedging Instrument | Foreign currency exchange derivatives    
ASSETS:    
Assets at fair value 44 47
LIABILITIES:    
Liabilities at fair value 54 40
Level 2 | Nonrecurring Basis | Equity securities of private entities    
ASSETS:    
Assets at fair value 0 30
Level 2 | Nonrecurring Basis | Long-lived assets | KAYAK    
ASSETS:    
Assets at fair value   0
Level 2 | Nonrecurring Basis | Goodwill | KAYAK    
ASSETS:    
Assets at fair value   0
Level 3 | Recurring Basis | Money market fund investments and certificates of deposit | Cash Equivalents and Restricted Cash Equivalents    
ASSETS:    
Assets at fair value 0 0
Level 3 | Recurring Basis | Equity securities with readily determinable fair values    
ASSETS:    
Assets at fair value 0 0
Level 3 | Recurring Basis | Not Designated as Hedging Instrument | Foreign currency exchange derivatives    
ASSETS:    
Assets at fair value 0 0
LIABILITIES:    
Liabilities at fair value 0 0
Level 3 | Nonrecurring Basis | Equity securities of private entities    
ASSETS:    
Assets at fair value $ 11 13
Level 3 | Nonrecurring Basis | Long-lived assets | KAYAK    
ASSETS:    
Assets at fair value [1]   179
Level 3 | Nonrecurring Basis | Goodwill | KAYAK    
ASSETS:    
Assets at fair value [1]   $ 203
[1] Fair value measurement as of September 30, 2025. See Note 11 to the Consolidated Financial Statements in the Company's Annual Report on Form 10-K for the year ended December 31, 2025 for additional information.