Segment Information (Financial Information by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information
Total revenues	$ 3,719	$ 3,485
Revenue from contract with customer	893	825
Equipment rentals gross profit (see calculation below)	1,356	1,346
Capital expenditures	791	653
Rental expenses	(2,363)	(2,139)
Total assets	28,050		$ 28,163
Sales of rental equipment
Segment Reporting Information
Capital expenditures incurred but not yet paid	123	158	77	$ 74
General Rentals Segment
Segment Reporting Information
Total revenues	2,573	2,546
Capital expenditures	521	506
Total assets	20,753		21,044
Specialty Segment
Segment Reporting Information
Total revenues	1,146	939
Capital expenditures	270	147
Total assets	7,297		$ 7,119
Equipment rentals
Segment Reporting Information
Total revenues	3,145	2,929
Revenue from contract with customer	319	269
Equipment rentals | General Rentals Segment
Segment Reporting Information
Total revenues	2,099	2,070
Equipment rentals | Specialty Segment
Segment Reporting Information
Total revenues	1,046	859
Sales of rental equipment
Segment Reporting Information
Total revenues	377	383
Revenue from contract with customer	377	383
Sales of rental equipment | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	330	346
Sales of rental equipment | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	47	37
Sales of new equipment
Segment Reporting Information
Total revenues	70	48
Revenue from contract with customer	70	48
Sales of new equipment | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	43	29
Sales of new equipment | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	27	19
Contractor supplies sales
Segment Reporting Information
Total revenues	36	36
Revenue from contract with customer	36	36
Contractor supplies sales | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	20	20
Contractor supplies sales | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	16	16
Service and other revenues
Segment Reporting Information
Total revenues	91	89
Revenue from contract with customer	91	89
Service and other revenues | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	81	81
Service and other revenues | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	10	8
Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	1,130	1,103
Depreciation of rental equipment	$ (637)	$ (582)
Equipment rentals gross profit | Revenues | Product concentration risk
Segment Reporting Information
Equipment rentals gross margin	35.90%	37.70%
Equipment rentals gross profit | General Rentals Segment
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	$ 679	$ 681
Depreciation of rental equipment	$ (488)	$ (488)
Equipment rentals gross profit | General Rentals Segment | Revenues | Product concentration risk
Segment Reporting Information
Equipment rentals gross margin	32.30%	32.90%
Equipment rentals gross profit | Specialty Segment
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	$ 451	$ 422
Depreciation of rental equipment	$ (149)	$ (94)
Equipment rentals gross profit | Specialty Segment | Revenues | Product concentration risk
Segment Reporting Information
Equipment rentals gross margin	43.10%	49.10%
Labor and benefits
Segment Reporting Information
Rental expenses	$ (526)	$ (488)
Labor and benefits | General Rentals Segment
Segment Reporting Information
Rental expenses	(406)	(390)
Labor and benefits | Specialty Segment
Segment Reporting Information
Rental expenses	(120)	(98)
Repairs and maintenance
Segment Reporting Information
Rental expenses	(246)	(243)
Repairs and maintenance | General Rentals Segment
Segment Reporting Information
Rental expenses	(193)	(199)
Repairs and maintenance | Specialty Segment
Segment Reporting Information
Rental expenses	(53)	(44)
Delivery
Segment Reporting Information
Rental expenses	(211)	(168)
Delivery | General Rentals Segment
Segment Reporting Information
Rental expenses	(115)	(102)
Delivery | Specialty Segment
Segment Reporting Information
Rental expenses	(96)	(66)
All other rental expenses
Segment Reporting Information
Rental expenses	(395)	(345)
All other rental expenses | General Rentals Segment
Segment Reporting Information
Rental expenses	(218)	(210)
All other rental expenses | Specialty Segment
Segment Reporting Information
Rental expenses	(177)	(135)
Gross profit from other lines of business
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	$ 226	$ 243