Condensed Consolidating Financial Information of Guarantor Subsidiaries - CONDENSED CONSOLIDATING STATEMENTS OF INCOME (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Equipment rentals										$ 5,715	$ 4,941	$ 4,949
Service and other revenues										118	102	94
Total revenues		$ 1,922	$ 1,766	$ 1,597	$ 1,356	$ 1,523	$ 1,508	$ 1,421	$ 1,310	6,641	5,762	5,817
Cost of equipment rentals, excluding depreciation										2,151	1,862	1,826
Depreciation of rental equipment										1,124	990	976
Cost of service and other revenues										59	41	38
Total cost of revenues										3,872	3,359	3,337
Gross profit		827	773	655	514	657	656	590	500	2,769	2,403	2,480
Selling, general and administrative expenses										903	719	714
Merger related costs		18								50	0	(26)
Restructuring charge		22								50	14	6
Non-rental depreciation and amortization										259	255	268
Operating income		462	448	340	257	402	412	347	254	1,507	1,415	1,518
Interest (income) expense, net										464	511	567
Other (income) expense, net										(5)	(5)	(12)
Income before (benefit) provision for income taxes										1,048	909	963
Provision (benefit) for income taxes										(298)	343	378
Income (loss) before equity in net earnings (loss) of subsidiaries										1,346	566	585
Equity in net earnings (loss) of subsidiaries										0	0	0
Net income		$ 897	$ 199	$ 141	$ 109	$ 153	$ 187	$ 134	$ 92	1,346	566	585
Other comprehensive income (loss)	[1]									67	32	(176)
Comprehensive income										1,413	598	409
Eliminations
Revenues:
Equipment rentals										0	0	0
Service and other revenues										0	0	0
Total revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										0	0	0
Cost of service and other revenues										0	0	0
Total cost of revenues										0	0	0
Gross profit										0	0	0
Selling, general and administrative expenses										0	0	0
Merger related costs										0		0
Restructuring charge										0	0	0
Non-rental depreciation and amortization										0	0	0
Operating income										0	0	0
Interest (income) expense, net										(5)	(5)	(5)
Other (income) expense, net										0	0	0
Income before (benefit) provision for income taxes										5	5	5
Provision (benefit) for income taxes										0	0	0
Income (loss) before equity in net earnings (loss) of subsidiaries										5	5	5
Equity in net earnings (loss) of subsidiaries										(1,162)	(383)	(473)
Net income										(1,157)	(378)	(468)
Other comprehensive income (loss)										(189)	(82)	490
Comprehensive income										(1,346)	(460)	22
Parent | Reportable Legal Entities
Revenues:
Equipment rentals										0	0	0
Service and other revenues										0	0	0
Total revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										0	0	0
Cost of service and other revenues										0	0	0
Total cost of revenues										0	0	0
Gross profit										0	0	0
Selling, general and administrative expenses										103	43	5
Merger related costs										0		0
Restructuring charge										0	0	0
Non-rental depreciation and amortization										15	15	15
Operating income										(118)	(58)	(20)
Interest (income) expense, net										(15)	(6)	(3)
Other (income) expense, net										(543)	(471)	(471)
Income before (benefit) provision for income taxes										440	419	454
Provision (benefit) for income taxes										144	154	201
Income (loss) before equity in net earnings (loss) of subsidiaries										296	265	253
Equity in net earnings (loss) of subsidiaries										1,050	301	332
Net income										1,346	566	585
Other comprehensive income (loss)										67	32	(176)
Comprehensive income										1,413	598	409
URNA | Reportable Legal Entities
Revenues:
Equipment rentals										5,253	4,524	4,452
Service and other revenues										102	87	80
Total revenues										6,076	5,252	5,218
Cost of equipment rentals, excluding depreciation										1,933	1,669	1,603
Depreciation of rental equipment										1,033	900	881
Cost of service and other revenues										51	35	33
Total cost of revenues										3,502	3,023	2,959
Gross profit										2,574	2,229	2,259
Selling, general and administrative expenses										682	579	596
Merger related costs										50		(26)
Restructuring charge										49	7	5
Non-rental depreciation and amortization										223	216	228
Operating income										1,570	1,427	1,456
Interest (income) expense, net										469	509	559
Other (income) expense, net										596	521	513
Income before (benefit) provision for income taxes										505	397	384
Provision (benefit) for income taxes										(469)	157	141
Income (loss) before equity in net earnings (loss) of subsidiaries										974	240	243
Equity in net earnings (loss) of subsidiaries										76	61	89
Net income										1,050	301	332
Other comprehensive income (loss)										67	32	(176)
Comprehensive income										1,117	333	156
Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Equipment rentals										0	0	0
Service and other revenues										0	0	0
Total revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										0	0	0
Cost of service and other revenues										0	0	0
Total cost of revenues										0	0	0
Gross profit										0	0	0
Selling, general and administrative expenses										0	0	1
Merger related costs										0		0
Restructuring charge										0	0	0
Non-rental depreciation and amortization										0	0	1
Operating income										0	0	(2)
Interest (income) expense, net										3	3	8
Other (income) expense, net										0	0	0
Income before (benefit) provision for income taxes										(3)	(3)	(10)
Provision (benefit) for income taxes										0	0	(5)
Income (loss) before equity in net earnings (loss) of subsidiaries										(3)	(3)	(5)
Equity in net earnings (loss) of subsidiaries										36	21	52
Net income										33	18	47
Other comprehensive income (loss)										67	28	(175)
Comprehensive income										100	46	(128)
Foreign | Reportable Legal Entities
Revenues:
Equipment rentals										462	417	497
Service and other revenues										16	15	14
Total revenues										565	510	599
Cost of equipment rentals, excluding depreciation										218	193	223
Depreciation of rental equipment										91	90	95
Cost of service and other revenues										8	6	5
Total cost of revenues										370	336	378
Gross profit										195	174	221
Selling, general and administrative expenses										80	72	79
Merger related costs										0		0
Restructuring charge										1	7	1
Non-rental depreciation and amortization										21	24	24
Operating income										93	71	117
Interest (income) expense, net										0	2	3
Other (income) expense, net										45	40	44
Income before (benefit) provision for income taxes										48	29	70
Provision (benefit) for income taxes										12	8	18
Income (loss) before equity in net earnings (loss) of subsidiaries										36	21	52
Equity in net earnings (loss) of subsidiaries										0	0	0
Net income										36	21	52
Other comprehensive income (loss)										55	22	(139)
Comprehensive income										91	43	(87)
SPV | Reportable Legal Entities
Revenues:
Equipment rentals										0	0	0
Service and other revenues										0	0	0
Total revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										0	0	0
Cost of service and other revenues										0	0	0
Total cost of revenues										0	0	0
Gross profit										0	0	0
Selling, general and administrative expenses										38	25	33
Merger related costs										0		0
Restructuring charge										0	0	0
Non-rental depreciation and amortization										0	0	0
Operating income										(38)	(25)	(33)
Interest (income) expense, net										12	8	5
Other (income) expense, net										(103)	(95)	(98)
Income before (benefit) provision for income taxes										53	62	60
Provision (benefit) for income taxes										15	24	23
Income (loss) before equity in net earnings (loss) of subsidiaries										38	38	37
Equity in net earnings (loss) of subsidiaries										0	0	0
Net income										38	38	37
Other comprehensive income (loss)										0	0	0
Comprehensive income										38	38	37
Rental Equipment
Revenues:
Sales revenue										550	496	538
Cost of goods sold										330	292	311
Rental Equipment | Eliminations
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
Rental Equipment | Parent | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
Rental Equipment | URNA | Reportable Legal Entities
Revenues:
Sales revenue										494	444	480
Cost of goods sold										302	265	279
Rental Equipment | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
Rental Equipment | Foreign | Reportable Legal Entities
Revenues:
Sales revenue										56	52	58
Cost of goods sold										28	27	32
Rental Equipment | SPV | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
New Equipment
Revenues:
Sales revenue										178	144	157
Cost of goods sold										152	119	131
New Equipment | Eliminations
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
New Equipment | Parent | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
New Equipment | URNA | Reportable Legal Entities
Revenues:
Sales revenue										157	129	137
Cost of goods sold										134	107	115
New Equipment | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
New Equipment | Foreign | Reportable Legal Entities
Revenues:
Sales revenue										21	15	20
Cost of goods sold										18	12	16
New Equipment | SPV | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
Contractor Supplies
Revenues:
Sales revenue										80	79	79
Cost of goods sold										56	55	55
Contractor Supplies | Eliminations
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
Contractor Supplies | Parent | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
Contractor Supplies | URNA | Reportable Legal Entities
Revenues:
Sales revenue										70	68	69
Cost of goods sold										49	47	48
Contractor Supplies | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										0	0	0
Contractor Supplies | Foreign | Reportable Legal Entities
Revenues:
Sales revenue										10	11	10
Cost of goods sold										7	8	7
Contractor Supplies | SPV | Reportable Legal Entities
Revenues:
Sales revenue										0	0	0
Cost of goods sold										$ 0	$ 0	$ 0

[1] There were no material reclassifications from accumulated other comprehensive loss reflected in other comprehensive income (loss) during the years ended December 31, 2017, 2016 or 2015. There is no tax impact related to the foreign currency translation adjustments, as the earnings are considered permanently reinvested. There were no material taxes associated with other comprehensive income (loss) during the years ended December 31, 2017, 2016 or 2015.