Acquisitions (Narrative - NES Acquisition) (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2017 USD ($) branch	Dec. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) employee	Dec. 31, 2015 USD ($)	Feb. 28, 2017 USD ($)
Business Acquisition [Line Items]
Rental assets		$ 7,824,000,000	$ 7,824,000,000	$ 6,189,000,000
Merger related costs		$ 18,000,000	$ 50,000,000	$ 0	$ (26,000,000)
Senior notes | 5 7/8 percent Senior Notes due 2026
Business Acquisition [Line Items]
Stated interest rate		5.875%	5.875%
Senior notes | 5 1/2 percent Senior Notes due 2027
Business Acquisition [Line Items]
Stated interest rate		5.50%	5.50%
NES and Neff Acquisitions
Business Acquisition [Line Items]
Increase in original equipment cost on rent, percent			18.20%
NES Rentals Holdings II, Inc.
Business Acquisition [Line Items]
Revenue reported by acquired entity for last annual period	$ 369,000,000
Consideration transferred	$ 960,000,000
Merger related costs			$ 17,000,000
NES Rentals Holdings II, Inc. | Senior notes | 5 7/8 percent Senior Notes due 2026
Business Acquisition [Line Items]
Debt instrument, face amount						$ 250,000,000
Stated interest rate	5.875%
NES Rentals Holdings II, Inc. | Senior notes | 5 1/2 percent Senior Notes due 2027
Business Acquisition [Line Items]
Debt instrument, face amount						$ 250,000,000
Stated interest rate	5.50%
NES Rentals Holdings II, Inc.
Business Acquisition [Line Items]
Number of branch locations | branch	73
Number of entity employees | employee				1,100
Rental assets				$ 900,000,000