Segment Information (Financial information by segment) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) location	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information
Equipment rentals	$ 1,166	$ 1,117
Sales of rental equipment	106	115
Sales of new equipment	39	30
Contractor supplies sales	18	19
Service and other revenues	27	29
Total revenues	1,356	1,310
Depreciation and amortization expense	310	310
Gross profit	514	500
Capital expenditures	241	123
Assets	$ 11,822		$ 11,988
General rentals
Segment Reporting Information
Number of geographic regions entity operates in (locations) | location	9
Equipment rentals	$ 977	955
Sales of rental equipment	96	106
Sales of new equipment	35	26
Contractor supplies sales	14	16
Service and other revenues	24	26
Total revenues	1,146	1,129
Depreciation and amortization expense	264	266
Capital expenditures	211	104
Assets	10,348		10,496
Trench, power and pump
Segment Reporting Information
Equipment rentals	189	162
Sales of rental equipment	10	9
Sales of new equipment	4	4
Contractor supplies sales	4	3
Service and other revenues	3	3
Total revenues	210	181
Depreciation and amortization expense	46	44
Capital expenditures	30	19
Assets	1,474		$ 1,492
Equipment rentals
Segment Reporting Information
Gross profit	444	425
Equipment rentals | General rentals
Segment Reporting Information
Gross profit	360	357
Equipment rentals | Trench, power and pump
Segment Reporting Information
Gross profit	$ 84	$ 68