Condensed Consolidating Financial Information of Guarantor Subsidiaries - CONDENSED CONSOLIDATING BALANCE SHEET (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 117	$ 352	$ 338	$ 312
Accounts receivable, net	1,203	1,233
Intercompany receivable (payable)	0	0
Inventory	94	75
Prepaid expenses and other assets	92	112
Total current assets	1,506	1,772
Rental equipment, net	8,213	7,824
Property and equipment, net	480	467
Investments in subsidiaries	0	0
Goodwill	4,096	4,082
Other intangible assets, net	798	875
Other long-term assets	15	10
Total assets	15,108	15,030
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	900	723
Accounts payable	859	409
Accrued expenses and other liabilities	470	536
Total current liabilities	2,229	1,668
Long-term debt	8,086	8,717
Deferred taxes	1,509	1,419
Other long-term liabilities	120	120
Total liabilities	11,944	11,924
Total stockholders’ equity (deficit)	3,164	3,106
Total liabilities and stockholders’ equity (deficit)	15,108	15,030
Eliminations
ASSETS
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany receivable (payable)	0	112
Inventory	0	0
Prepaid expenses and other assets	0	(224)
Total current assets	0	(112)
Rental equipment, net	0	0
Property and equipment, net	0	0
Investments in subsidiaries	(3,900)	(4,429)
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	(3,900)	(4,541)
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	0	0
Accounts payable	0	0
Accrued expenses and other liabilities	0	0
Total current liabilities	0	0
Long-term debt	0	0
Deferred taxes	0	0
Other long-term liabilities	0	0
Total liabilities	0	0
Total stockholders’ equity (deficit)	(3,900)	(4,541)
Total liabilities and stockholders’ equity (deficit)	(3,900)	(4,541)
Parent | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany receivable (payable)	1,197	887
Inventory	0	0
Prepaid expenses and other assets	0	4
Total current assets	1,197	891
Rental equipment, net	0	0
Property and equipment, net	45	41
Investments in subsidiaries	1,939	2,194
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	6	3
Total assets	3,187	3,129
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	1	1
Accounts payable	0	0
Accrued expenses and other liabilities	0	0
Total current liabilities	1	1
Long-term debt	0	1
Deferred taxes	22	21
Other long-term liabilities	0	0
Total liabilities	23	23
Total stockholders’ equity (deficit)	3,164	3,106
Total liabilities and stockholders’ equity (deficit)	$ 3,187	3,129
URNA
Condensed Financial Information Other Details [Abstract]
Ownership percentage in subsidiaries	100.00%
URNA | Reportable Legal Entities
ASSETS
Cash and cash equivalents	$ 44	23	9	21
Accounts receivable, net	0	56
Intercompany receivable (payable)	(1,083)	(677)
Inventory	85	68
Prepaid expenses and other assets	89	219
Total current assets	(865)	(311)
Rental equipment, net	7,642	7,264
Property and equipment, net	354	352
Investments in subsidiaries	1,053	1,148
Goodwill	3,842	3,815
Other intangible assets, net	758	827
Other long-term assets	9	7
Total assets	12,793	13,102
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	28	25
Accounts payable	787	366
Accrued expenses and other liabilities	429	477
Total current liabilities	1,244	868
Long-term debt	8,074	8,596
Deferred taxes	1,416	1,324
Other long-term liabilities	120	120
Total liabilities	10,854	10,908
Total stockholders’ equity (deficit)	1,939	2,194
Total liabilities and stockholders’ equity (deficit)	$ 12,793	13,102
Guarantor Subsidiaries
Condensed Financial Information Other Details [Abstract]
Ownership percentage in subsidiaries	100.00%
Guarantor Subsidiaries | Reportable Legal Entities
ASSETS
Cash and cash equivalents	$ 0	0	0	0
Accounts receivable, net	0	0
Intercompany receivable (payable)	(98)	(198)
Inventory	0	0
Prepaid expenses and other assets	0	111
Total current assets	(98)	(87)
Rental equipment, net	0	0
Property and equipment, net	41	32
Investments in subsidiaries	908	1,087
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	851	1,032
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	0	0
Accounts payable	0	0
Accrued expenses and other liabilities	13	17
Total current liabilities	13	17
Long-term debt	9	117
Deferred taxes	0	0
Other long-term liabilities	0	0
Total liabilities	22	134
Total stockholders’ equity (deficit)	829	898
Total liabilities and stockholders’ equity (deficit)	851	1,032
Non-Guarantor Subsidiaries - Foreign | Reportable Legal Entities
ASSETS
Cash and cash equivalents	73	329	329	291
Accounts receivable, net	109	119
Intercompany receivable (payable)	(16)	(124)
Inventory	9	7
Prepaid expenses and other assets	3	2
Total current assets	178	333
Rental equipment, net	571	560
Property and equipment, net	40	42
Investments in subsidiaries	0	0
Goodwill	254	267
Other intangible assets, net	40	48
Other long-term assets	0	0
Total assets	1,083	1,250
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	2	2
Accounts payable	72	43
Accrued expenses and other liabilities	27	41
Total current liabilities	101	86
Long-term debt	3	3
Deferred taxes	71	74
Other long-term liabilities	0	0
Total liabilities	175	163
Total stockholders’ equity (deficit)	908	1,087
Total liabilities and stockholders’ equity (deficit)	1,083	1,250
Non-Guarantor Subsidiaries - SPV | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	1,094	1,058
Intercompany receivable (payable)	0	0
Inventory	0	0
Prepaid expenses and other assets	0	0
Total current assets	1,094	1,058
Rental equipment, net	0	0
Property and equipment, net	0	0
Investments in subsidiaries	0	0
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	1,094	1,058
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	869	695
Accounts payable	0	0
Accrued expenses and other liabilities	1	1
Total current liabilities	870	696
Long-term debt	0	0
Deferred taxes	0	0
Other long-term liabilities	0	0
Total liabilities	870	696
Total stockholders’ equity (deficit)	224	362
Total liabilities and stockholders’ equity (deficit)	1,094	$ 1,058
ABL Facility
Condensed Financial Information Other Details [Abstract]
Line of credit facility, restricted payment capacity	2,001
ABL Facility | URNA
Condensed Financial Information Other Details [Abstract]
Line of credit facility, restricted payment capacity	$ 804
Senior notes | 5 3/4 percent Senior Notes due 2024
Condensed Financial Information Other Details [Abstract]
Stated interest rate	5.75%