Acquisitions (Narrative) (Details) $ in Millions	1 Months Ended		3 Months Ended
	Oct. 31, 2017 USD ($) branch state	Apr. 30, 2017 USD ($) branch	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($) employee	Dec. 31, 2016 USD ($) employee
Business Acquisition [Line Items]
Rental equipment, net			$ 7,678		$ 7,824
Merger related costs			$ 1	$ 2
Increase in volume of OEC on rent (as a percent)			26.10%
NES Rentals Holdings II, Inc.
Business Acquisition [Line Items]
Revenue reported by acquired entity for last annual period		$ 369
Aggregate consideration paid		$ 960
Merger related costs			$ 0
Neff Corporation
Business Acquisition [Line Items]
Revenue reported by acquired entity for last annual period	$ 413
Aggregate consideration paid	1,316
Equity interests issued and issuable	$ 7
NES Rentals Holdings II, Inc.
Business Acquisition [Line Items]
Number of rental locations (branch) | branch		73
Number of employees | employee							1,100
Rental equipment, net							$ 900
Neff Corporation
Business Acquisition [Line Items]
Number of rental locations (branch) | branch	69
Number of employees | employee						1,100
Rental equipment, net						$ 860
Number of states | state	14