Segment Information (Financial information by segment) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) location	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information
Equipment rentals	$ 1,117	$ 1,125
Sales of rental equipment	115	116
Sales of new equipment	30	33
Contractor supplies sales	19	18
Service and other revenues	29	23
Total revenues	1,310	1,315
Depreciation and amortization expense	310	304
Gross profit	500	524
Capital expenditures	123	345
Assets	11,784		$ 12,083
Operating Segments
Segment Reporting Information
Assets	$ 11,784		12,083
Operating Segments | General rentals
Segment Reporting Information
Number of geographic regions entity operates in (locations) | location	9
Equipment rentals	$ 955	976
Sales of rental equipment	106	108
Sales of new equipment	26	26
Contractor supplies sales	16	15
Service and other revenues	26	19
Total revenues	1,129	1,144
Depreciation and amortization expense	266	262
Capital expenditures	104	311
Assets	10,281		10,561
Operating Segments | Trench, power and pump
Segment Reporting Information
Equipment rentals	162	149
Sales of rental equipment	9	8
Sales of new equipment	4	7
Contractor supplies sales	3	3
Service and other revenues	3	4
Total revenues	181	171
Depreciation and amortization expense	44	42
Capital expenditures	19	34
Assets	1,503		$ 1,522
Equipment rentals
Segment Reporting Information
Gross profit	425	446
Equipment rentals | Operating Segments | General rentals
Segment Reporting Information
Gross profit	357	383
Equipment rentals | Operating Segments | Trench, power and pump
Segment Reporting Information
Gross profit	$ 68	$ 63