Acquisitions (Pro Forma Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues	$ 3,296	$ 3,051	$ 2,771	$ 2,524	$ 2,776	$ 2,596	$ 2,287	$ 2,057	$ 11,642	$ 9,716	$ 8,530
Pro forma revenues									12,469	10,702
Income (loss) before provision (benefit) for income taxes									2,802	1,846	1,139
Pro forma pretax income										1,840
Loss on extinguishment of debt									17	30	183
Merger related costs									0	3	$ 0
Impact of fair value mark-ups/useful life changes on depreciation
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										(11)
Impact of the fair value mark-up of acquired fleet on cost of rental equipment sales
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										(6)
Intangible asset amortization
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										(11)
Interest expense
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										(6)
Elimination of historic interest
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										23
Elimination of merger related costs
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										12
Elimination of changes in the valuation of bifurcated derivatives in convertible notes
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										(16)
United Rentals
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues									11,642	9,716
United Rentals and General Finance Corporation
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Income (loss) before provision (benefit) for income taxes										1,855
Loss on extinguishment of debt									12
General Finance Corporation
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues									0	144
Income (loss) before provision (benefit) for income taxes										9
Merger related costs									9
Ahern Rentals
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Revenues									$ 827	$ 842