Acquisitions (Narrative) (Details) $ in Millions	1 Months Ended			3 Months Ended	9 Months Ended
	Jul. 31, 2018 USD ($) employee location	Oct. 31, 2017 USD ($) branch state	Apr. 30, 2017 USD ($) branch	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($) employee	Dec. 31, 2016 USD ($) employee
Business Acquisition [Line Items]
Rental equipment, net				$ 8,910	$ 8,910	$ 7,824
Increase in volume of OEC on rent (as a percent)				17.80%	19.60%
NES Rentals Holdings II, Inc.
Business Acquisition [Line Items]
Revenue reported by acquired entity for last annual period			$ 369
Aggregate consideration paid			$ 960
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
BakerCorp
Business Acquisition [Line Items]
Revenue reported by acquired entity for last annual period	$ 295
Aggregate consideration paid	$ 724
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
BakerCorp
Business Acquisition [Line Items]
Number of employees | employee	950
United States And Canada | BakerCorp
Business Acquisition [Line Items]
Number of rental locations (branch) | location	46
France, Germany, United Kingdom And Netherlands | BakerCorp
Business Acquisition [Line Items]
Number of rental locations (branch) | location	11