SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details)		12 Months Ended
		Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2017 USD ($)
Significant Accounting Policies [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]		Cost of revenues
Compensation costs from retirement savings plan		$ 137,000,000	$ 80,000,000	$ 75,000,000
Advertising costs		635,000,000	470,000,000	276,000,000
Allowance for credit losses		191,000,000	187,000,000
Change in allowance for credit losses		27,000,000	22,000,000	136,000,000
Goodwill impairment charge		0	0	0
Self-insurance reserve, current		130,000,000	124,000,000
Self-insurance reserve, noncurrent		$ 287,000,000	290,000,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Avendra LLC
Significant Accounting Policies [Line Items]
Gain (loss) on disposal					$ 664,000,000
Gain (loss) on disposal, net of tax					$ 425,000,000
Measurement Input, Discount Rate | Valuation Technique, Discounted Cash Flow
Significant Accounting Policies [Line Items]
Self insurance review, measurement input		0.0425
Deferred revenue
Significant Accounting Policies [Line Items]
Change in customer contract liability		$ (196,000,000)
Customer contract liability		1,331,000,000	1,527,000,000
Revenue recognized from customer contract liability		330,000,000
Guest loyalty program
Significant Accounting Policies [Line Items]
Change in customer contract liability		123,000,000
Customer contract liability		6,594,000,000	6,471,000,000
Current deferred revenue		3,314,000,000	2,522,000,000
Revenue recognized from customer contract liability		2,692,000,000
Reclassification from deferred revenue		241,000,000
Change in customer contract liability from change in estimates		106,000,000
Reimbursements
Significant Accounting Policies [Line Items]
Cost of revenues	[1]	15,141,000,000	10,322,000,000	8,435,000,000
Reimbursements | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Avendra LLC
Significant Accounting Policies [Line Items]
Cost of revenues		69,000,000	56,000,000	62,000,000
Cost of revenues, net of tax		52,000,000	42,000,000	$ 46,000,000
Costs Incurred to Fulfill Contracts
Significant Accounting Policies [Line Items]
Capitalized costs		$ 379,000,000	$ 368,000,000

[1] See Note 15 for disclosure of related party amounts.