Segment Information (Reconciliation to consolidated totals) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total equipment rentals gross profit	$ 657	$ 656	$ 590	$ 500	$ 648	$ 690	$ 618	$ 524	$ 2,403	$ 2,480	$ 2,432
Selling, general and administrative expenses									(719)	(714)	(758)
Merger related costs									0	26	(11)
Restructuring charge									(14)	(6)	1
Non-rental depreciation and amortization									(255)	(268)	(273)
Interest expense, net									(511)	(567)	(555)
Other income, net									5	12	14
Income before provision for income taxes									909	963	850
Equipment rentals
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total equipment rentals gross profit									2,089	2,147	2,092
Other products and services
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total equipment rentals gross profit									$ 314	$ 333	$ 340