Segment Information (Financial information by segment) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) location	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) location	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information
Equipment rentals	$ 1,367	$ 1,204	$ 2,533	$ 2,321
Sales of rental equipment	133	134	239	249
Sales of new equipment	47	36	86	66
Contractor supplies sales	21	22	39	41
Service and other revenues	29	25	56	54
Total revenues	1,597	1,421	2,953	2,731
Depreciation and amortization expense	330	306	640	616
Gross profit	655	590	1,169	1,090
Capital expenditures			968	764
Assets	$ 13,284		$ 13,284		$ 11,988
General rentals
Segment Reporting Information
Number of geographic regions entity operates in (locations) | location	10		10
Equipment rentals	$ 1,143	1,015	$ 2,120	1,970
Sales of rental equipment	122	125	218	231
Sales of new equipment	43	31	78	57
Contractor supplies sales	18	17	32	33
Service and other revenues	26	22	50	48
Total revenues	1,352	1,210	2,498	2,339
Depreciation and amortization expense	285	259	549	525
Capital expenditures			863	692
Assets	11,747		11,747		10,496
Trench, power and pump
Segment Reporting Information
Equipment rentals	224	189	413	351
Sales of rental equipment	11	9	21	18
Sales of new equipment	4	5	8	9
Contractor supplies sales	3	5	7	8
Service and other revenues	3	3	6	6
Total revenues	245	211	455	392
Depreciation and amortization expense	45	47	91	91
Capital expenditures			105	72
Assets	1,537		1,537		$ 1,492
Equipment rentals
Segment Reporting Information
Gross profit	576	506	1,020	931
Equipment rentals | General rentals
Segment Reporting Information
Gross profit	465	417	825	774
Equipment rentals | Trench, power and pump
Segment Reporting Information
Gross profit	$ 111	$ 89	$ 195	$ 157