Segment Information (Financial Information by Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information
Total revenues	$ 4,229	$ 3,992	$ 11,891	$ 11,250
Revenue from contract with customer	938	874	2,703	2,569
Equipment rentals gross profit (see calculation below)	1,665	1,648	4,554	4,512
Capital expenditures			4,033	3,553
Rental expenses	(2,564)	(2,344)	(7,337)	(6,738)
Total assets	30,065		30,065		$ 28,163
Sales of rental equipment
Segment Reporting Information
Capital expenditures incurred but not yet paid			261	183	77	$ 74
General Rentals Segment
Segment Reporting Information
Total revenues	2,826	2,745	8,097	7,944
Capital expenditures			3,049	2,738
Total assets	22,147		22,147		21,044
Specialty Segment
Segment Reporting Information
Total revenues	1,403	1,247	3,794	3,306
Capital expenditures			984	815
Total assets	7,918		7,918		$ 7,119
Equipment rentals
Segment Reporting Information
Total revenues	3,665	3,463	10,225	9,607
Revenue from contract with customer	374	345	1,037	926
Equipment rentals | General Rentals Segment
Segment Reporting Information
Total revenues	2,400	2,327	6,767	6,606
Equipment rentals | Specialty Segment
Segment Reporting Information
Total revenues	1,265	1,136	3,458	3,001
Sales of rental equipment
Segment Reporting Information
Total revenues	333	321	1,027	1,069
Revenue from contract with customer	333	321	1,027	1,069
Sales of rental equipment | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	274	274	876	933
Sales of rental equipment | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	59	47	151	136
Sales of new equipment
Segment Reporting Information
Total revenues	95	77	240	186
Revenue from contract with customer	95	77	240	186
Sales of new equipment | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	45	36	137	92
Sales of new equipment | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	50	41	103	94
Contractor supplies sales
Segment Reporting Information
Total revenues	43	38	120	116
Revenue from contract with customer	43	38	120	116
Contractor supplies sales | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	23	22	65	65
Contractor supplies sales | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	20	16	55	51
Service and other revenues
Segment Reporting Information
Total revenues	93	93	279	272
Revenue from contract with customer	93	93	279	272
Service and other revenues | General Rentals Segment
Segment Reporting Information
Revenue from contract with customer	84	86	252	248
Service and other revenues | Specialty Segment
Segment Reporting Information
Revenue from contract with customer	9	7	27	24
Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	1,451	1,442	3,902	3,830
Depreciation of rental equipment	$ (684)	$ (629)	$ (1,972)	$ (1,819)
Equipment rentals gross profit | Revenues | Product concentration risk
Segment Reporting Information
Equipment rentals gross margin	39.60%	41.60%	38.20%	39.90%
Equipment rentals gross profit | General Rentals Segment
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	$ 881	$ 874	$ 2,356	$ 2,357
Depreciation of rental equipment	$ (512)	$ (497)	$ (1,497)	$ (1,465)
Equipment rentals gross profit | General Rentals Segment | Revenues | Product concentration risk
Segment Reporting Information
Equipment rentals gross margin	36.70%	37.60%	34.80%	35.70%
Equipment rentals gross profit | Specialty Segment
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	$ 570	$ 568	$ 1,546	$ 1,473
Depreciation of rental equipment	$ (172)	$ (132)	$ (475)	$ (354)
Equipment rentals gross profit | Specialty Segment | Revenues | Product concentration risk
Segment Reporting Information
Equipment rentals gross margin	45.10%	50.00%	44.70%	49.10%
Labor and benefits
Segment Reporting Information
Rental expenses	$ (550)	$ (511)	$ (1,619)	$ (1,497)
Labor and benefits | General Rentals Segment
Segment Reporting Information
Rental expenses	(416)	(396)	(1,237)	(1,178)
Labor and benefits | Specialty Segment
Segment Reporting Information
Rental expenses	(134)	(115)	(382)	(319)
Repairs and maintenance
Segment Reporting Information
Rental expenses	(294)	(272)	(808)	(773)
Repairs and maintenance | General Rentals Segment
Segment Reporting Information
Rental expenses	(228)	(214)	(630)	(619)
Repairs and maintenance | Specialty Segment
Segment Reporting Information
Rental expenses	(66)	(58)	(178)	(154)
Delivery
Segment Reporting Information
Rental expenses	(274)	(228)	(732)	(602)
Delivery | General Rentals Segment
Segment Reporting Information
Rental expenses	(141)	(126)	(384)	(346)
Delivery | Specialty Segment
Segment Reporting Information
Rental expenses	(133)	(102)	(348)	(256)
All other rental expenses
Segment Reporting Information
Rental expenses	(412)	(381)	(1,192)	(1,086)
All other rental expenses | General Rentals Segment
Segment Reporting Information
Rental expenses	(222)	(220)	(663)	(641)
All other rental expenses | Specialty Segment
Segment Reporting Information
Rental expenses	(190)	(161)	(529)	(445)
Gross profit from other lines of business
Segment Reporting Information
Equipment rentals gross profit (see calculation below)	$ 214	$ 206	$ 652	$ 682