Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Information [Abstract]
Total revenues	$ 1,523	$ 1,550	$ 1,429	$ 1,315	$ 1,564	$ 1,544	$ 1,399	$ 1,178	$ 5,817	$ 5,685	$ 4,955
Gross profit	648	690	618	524	707	688	589	448	2,480	2,432	1,987
Operating income	397	446	375	300	426	422	325	218	1,518	1,391	1,078
Net income	$ 169	$ 215	$ 86	$ 115	$ 194	$ 192	$ 94	$ 60	$ 585	$ 540	$ 387
Basic earnings per share (in dollars per share)	$ 1.82	$ 2.28	$ 0.89	$ 1.19	$ 1.96	$ 1.95	$ 0.98	$ 0.63	$ 6.14	$ 5.54	$ 4.14
Diluted earnings per share (in dollars per share)	$ 1.81	2.25	0.88	1.16	$ 1.88	1.84	0.90	0.56	$ 6.07	$ 5.15	$ 3.64
Increase (decrease) in stock compensation, net	$ (14)				$ 14
Restructuring charge									$ 6	$ (1)	$ 12
Refund from tax settlement	5								$ 5
Reduction in cost of equipment rentals, excluding depreciation	5
Increase in valuation allowance	$ 5
Increase (decrease) in bad debt expense					$ 8
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Merger related costs (in dollars per share)	$ 0.00	0.00	0.00	0.17	$ 0.02	(0.02)	(0.05)	(0.01)	$ 0.17	$ (0.06)
Merger related intangible asset amortization (in dollars per share)	(0.28)	(0.28)	(0.27)	(0.32)	(0.30)	(0.29)	(0.29)	(0.22)	(1.15)	(1.10)
Impact on depreciation related to acquired RSC fleet and property and equipment (in dollars per share)	0.00	0.00	0.00	0.01	0.01	0.01	0.01	0.00	0.02	0.03
Impact of the fair value mark-up of acquired RSC fleet (in dollars per share)	(0.07)	(0.04)	(0.04)	(0.04)	(0.05)	(0.05)	(0.06)	(0.05)	(0.19)	(0.21)
Impact on interest expense related to fair value adjustment of acquired RSC indebtedness (in dollars per share)	0.00	0.00	0.00	0.01	0.01	0.00	0.01	0.01	0.02	0.03
Restructuring charge (in dollars per share)	(0.03)	0.00	0.00	0.00	0.00	0.01	0.01	(0.01)	(0.04)	0.01
Loss on extinguishment of debt securities and amendment of ABL facility (in dollars per share)	$ 0.00	$ 0.00	$ (0.76)	$ (0.01)	$ 0.00	$ (0.02)	$ (0.38)	$ (0.06)	$ (0.78)	$ (0.46)
2015-2016 Cost Savings Restructuring Program
Selected Quarterly Financial Information [Abstract]
Restructuring charge	$ 4								$ 4