Segment Information (Reconciliation to Consolidated Totals) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gross profit	$ 1,562	$ 1,585	$ 1,425	$ 1,241	$ 1,488	$ 1,366	$ 1,150	$ 992	$ 5,813	$ 4,996	$ 3,853
Selling, general and administrative expenses									(1,527)	(1,400)	(1,199)
Merger related costs (1)									0	0	(3)
Restructuring charge (2)									(28)	0	(2)
Non-rental depreciation and amortization									(431)	(364)	(372)
Interest expense, net									(635)	(445)	(424)
Other income (expense), net									19	15	(7)
Income before provision for income taxes									3,211	2,802	1,846
Equipment rentals
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gross profit									4,814	4,245	3,267
Other products and services
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gross profit									$ 999	$ 751	$ 586