Condensed Consolidating Financial Information of Guarantor Subsidiaries - CONDENSED CONSOLIDATING STATEMENTS OF INCOME (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Revenues		$ 2,306	$ 2,116	$ 1,891	$ 1,734	$ 1,922	$ 1,766	$ 1,597	$ 1,356	$ 8,047	$ 6,641	$ 5,762
Cost of equipment rentals, excluding depreciation										2,614	2,151	1,862
Depreciation of rental equipment										1,363	1,124	990
Total cost of revenues										4,683	3,872	3,359
Gross profit		998	938	782	646	827	773	655	514	3,364	2,769	2,403
Selling, general and administrative expenses										1,038	903	719
Merger related costs		22				18				36	50	0
Restructuring charge		16				22				31	50	14
Non-rental depreciation and amortization										308	259	255
Operating income		563	578	470	340	462	448	340	257	1,951	1,507	1,415
Interest (income) expense, net										481	464	511
Other (income) expense, net										(6)	(5)	(5)
Income before provision (benefit) for income taxes										1,476	1,048	909
Provision for income taxes										380	(298)	343
Income (loss) before equity in net earnings (loss) of subsidiaries										1,096	1,346	566
Equity in net earnings (loss) of subsidiaries										0	0	0
Net income		$ 310	$ 333	$ 270	$ 183	$ 897	$ 199	$ 141	$ 109	1,096	1,346	566
Other comprehensive (loss) income	[1]									(86)	67	32
Comprehensive income										1,010	1,413	598
Eliminations
Revenues:
Revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										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										(1)	(5)	(5)
Other (income) expense, net										0	0	0
Income before provision (benefit) for income taxes										1	5	5
Provision for income taxes										0	0	0
Income (loss) before equity in net earnings (loss) of subsidiaries										1	5	5
Equity in net earnings (loss) of subsidiaries										(751)	(1,162)	(383)
Net income										(750)	(1,157)	(378)
Other comprehensive (loss) income										273	(189)	(82)
Comprehensive income										(477)	(1,346)	(460)
Parent
Revenues:
Merger related costs											0
Parent | Reportable Legal Entities
Revenues:
Revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										0	0	0
Total cost of revenues										0	0	0
Gross profit										0	0	0
Selling, general and administrative expenses										25	103	43
Merger related costs										0
Restructuring charge										0	0	0
Non-rental depreciation and amortization										17	15	15
Operating income										(42)	(118)	(58)
Interest (income) expense, net										(39)	(15)	(6)
Other (income) expense, net										(657)	(543)	(471)
Income before provision (benefit) for income taxes										654	440	419
Provision for income taxes										164	144	154
Income (loss) before equity in net earnings (loss) of subsidiaries										490	296	265
Equity in net earnings (loss) of subsidiaries										606	1,050	301
Net income										1,096	1,346	566
Other comprehensive (loss) income										(86)	67	32
Comprehensive income										1,010	1,413	598
URNA | Reportable Legal Entities
Revenues:
Revenues										7,387	6,076	5,252
Cost of equipment rentals, excluding depreciation										2,370	1,933	1,669
Depreciation of rental equipment										1,258	1,033	900
Total cost of revenues										4,268	3,502	3,023
Gross profit										3,119	2,574	2,229
Selling, general and administrative expenses										860	682	579
Merger related costs										36	50
Restructuring charge										29	49	7
Non-rental depreciation and amortization										266	223	216
Operating income										1,928	1,570	1,427
Interest (income) expense, net										497	469	509
Other (income) expense, net										742	596	521
Income before provision (benefit) for income taxes										689	505	397
Provision for income taxes										181	(469)	157
Income (loss) before equity in net earnings (loss) of subsidiaries										508	974	240
Equity in net earnings (loss) of subsidiaries										98	76	61
Net income										606	1,050	301
Other comprehensive (loss) income										(86)	67	32
Comprehensive income										520	1,117	333
Guarantor Subsidiaries
Revenues:
Merger related costs											0
Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										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
Restructuring charge										0	0	0
Non-rental depreciation and amortization										0	0	0
Operating income										0	0	0
Interest (income) expense, net										0	3	3
Other (income) expense, net										0	0	0
Income before provision (benefit) for income taxes										0	(3)	(3)
Provision for income taxes										0	0	0
Income (loss) before equity in net earnings (loss) of subsidiaries										0	(3)	(3)
Equity in net earnings (loss) of subsidiaries										47	36	21
Net income										47	33	18
Other comprehensive (loss) income										(82)	67	28
Comprehensive income										(35)	100	46
Foreign | Reportable Legal Entities
Revenues:
Revenues										660	565	510
Cost of equipment rentals, excluding depreciation										244	218	193
Depreciation of rental equipment										105	91	90
Total cost of revenues										415	370	336
Gross profit										245	195	174
Selling, general and administrative expenses										96	80	72
Merger related costs										0	0
Restructuring charge										2	1	7
Non-rental depreciation and amortization										25	21	24
Operating income										122	93	71
Interest (income) expense, net										0	0	2
Other (income) expense, net										51	45	40
Income before provision (benefit) for income taxes										71	48	29
Provision for income taxes										20	12	8
Income (loss) before equity in net earnings (loss) of subsidiaries										51	36	21
Equity in net earnings (loss) of subsidiaries										0	0	0
Net income										51	36	21
Other comprehensive (loss) income										(105)	55	22
Comprehensive income										(54)	91	43
SPV | Reportable Legal Entities
Revenues:
Revenues										0	0	0
Cost of equipment rentals, excluding depreciation										0	0	0
Depreciation of rental equipment										0	0	0
Total cost of revenues										0	0	0
Gross profit										0	0	0
Selling, general and administrative expenses										57	38	25
Merger related costs										0	0
Restructuring charge										0	0	0
Non-rental depreciation and amortization										0	0	0
Operating income										(57)	(38)	(25)
Interest (income) expense, net										24	12	8
Other (income) expense, net										(142)	(103)	(95)
Income before provision (benefit) for income taxes										61	53	62
Provision for income taxes										15	15	24
Income (loss) before equity in net earnings (loss) of subsidiaries										46	38	38
Equity in net earnings (loss) of subsidiaries										0	0	0
Net income										46	38	38
Other comprehensive (loss) income										0	0	0
Comprehensive income										46	38	38
Total equipment rentals
Revenues:
Revenues										6,940	5,715	4,941
Total equipment rentals | Eliminations
Revenues:
Revenues										0	0	0
Total equipment rentals | Parent | Reportable Legal Entities
Revenues:
Revenues										0	0	0
Total equipment rentals | URNA | Reportable Legal Entities
Revenues:
Revenues										6,388	5,253	4,524
Total equipment rentals | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenues										0	0	0
Total equipment rentals | Foreign | Reportable Legal Entities
Revenues:
Revenues										552	462	417
Total equipment rentals | SPV | Reportable Legal Entities
Revenues:
Revenues										0	0	0
Sales of rental equipment
Revenues:
Revenue from contract with customer, excluding assessed tax										664	550	496
Cost of goods and services sold										386	330	292
Sales of rental equipment | Eliminations
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Sales of rental equipment | Parent | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Sales of rental equipment | URNA | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										609	494	444
Cost of goods and services sold										358	302	265
Sales of rental equipment | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Sales of rental equipment | Foreign | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										55	56	52
Cost of goods and services sold										28	28	27
Sales of rental equipment | SPV | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Sales of new equipment
Revenues:
Revenue from contract with customer, excluding assessed tax										208	178	144
Cost of goods and services sold										179	152	119
Sales of new equipment | Eliminations
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Sales of new equipment | Parent | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Sales of new equipment | URNA | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										184	157	129
Cost of goods and services sold										159	134	107
Sales of new equipment | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Sales of new equipment | Foreign | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										24	21	15
Cost of goods and services sold										20	18	12
Sales of new equipment | SPV | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Contractor supplies sales
Revenues:
Revenue from contract with customer, excluding assessed tax										91	80	79
Cost of goods and services sold										60	56	55
Contractor supplies sales | Eliminations
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Contractor supplies sales | Parent | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Contractor supplies sales | URNA | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										80	70	68
Cost of goods and services sold										52	49	47
Contractor supplies sales | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Contractor supplies sales | Foreign | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										11	10	11
Cost of goods and services sold										8	7	8
Contractor supplies sales | SPV | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Service and other revenues
Revenues:
Revenue from contract with customer, excluding assessed tax										144	118	102
Cost of goods and services sold										81	59	41
Service and other revenues | Eliminations
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Service and other revenues | Parent | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Service and other revenues | URNA | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										126	102	87
Cost of goods and services sold										71	51	35
Service and other revenues | Guarantor Subsidiaries | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services sold										0	0	0
Service and other revenues | Foreign | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										18	16	15
Cost of goods and services sold										10	8	6
Service and other revenues | SPV | Reportable Legal Entities
Revenues:
Revenue from contract with customer, excluding assessed tax										0	0	0
Cost of goods and services 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, 2018, 2017 or 2016. There is no tax impact related to the foreign currency translation adjustments, as the earnings are considered permanently reinvested (see note 13 to the consolidated financial statements for further discussion addressing this determination). There were no material taxes associated with other comprehensive income (loss) during the years ended December 31, 2018, 2017 or 2016.