SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Summary of Significant Accounting Policies [Line Items]
Derivative contracts, net	$ 5,000,000	$ 47,000,000
Depreciation and amortization expense related to property and equipment	2,341,000,000	2,107,000,000	$ 1,998,000,000
Amortization of capitalized software	340,000,000	307,000,000	301,000,000
Net book value of capitalized software	932,000,000	891,000,000
Fuel card obligation	1,100,000,000	1,100,000,000
Advertising expense	347,000,000	302,000,000	$ 198,000,000
Fuel Card Obligation
Summary of Significant Accounting Policies [Line Items]
Purchasing card maximum limit	1,100,000,000
Fuel card obligation	$ 1,100,000,000	$ 1,100,000,000
Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated residual value (percent)	5.00%
Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated residual value (percent)	10.00%
Software and software development costs | Minimum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life	3 years
Software and software development costs | Maximum
Summary of Significant Accounting Policies [Line Items]
Estimated useful life	15 years