Franchising, Marketing and Reservation Activities - Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Millions  | 
Jun. 30, 2025  | 
Dec. 31, 2024  | 
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| Franchisees and hotel owners | ||
| Disaggregation of Revenue [Line Items] | ||
| Development advance notes | $ 356 | $ 308 | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount, after allowance for credit loss, of financing receivable, classified as noncurrent. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef 
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- Details 
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