Condensed Consolidating Financial Information of Guarantor Subsidiaries - CONDENSED CONSOLIDATING BALANCE SHEET (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents	$ 65	$ 352	$ 324	$ 312
Accounts receivable, net	1,438	1,233
Intercompany receivable (payable)	0	0
Inventory	104	75
Prepaid expenses and other assets	85	112
Total current assets	1,692	1,772
Rental equipment, net	8,910	7,824
Property and equipment, net	529	467
Investments in subsidiaries	0	0
Goodwill	4,313	4,082
Other intangible assets, net	895	875
Other long-term assets	15	10
Total assets	16,354	15,030
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	896	723
Accounts payable	688	409
Accrued expenses and other liabilities	503	536
Total current liabilities	2,087	1,668
Long-term debt	9,182	8,717
Deferred taxes	1,628	1,419
Other long-term liabilities	123	120
Total liabilities	13,020	11,924
Total stockholders’ equity (deficit)	3,334	3,106
Total liabilities and stockholders’ equity (deficit)	16,354	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	(4,495)	(4,429)
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	(4,495)	(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)	(4,495)	(4,541)
Total liabilities and stockholders’ equity (deficit)	(4,495)	(4,541)
Parent | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany receivable (payable)	1,325	887
Inventory	0	0
Prepaid expenses and other assets	0	4
Total current assets	1,325	891
Rental equipment, net	0	0
Property and equipment, net	51	41
Investments in subsidiaries	1,973	2,194
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	7	3
Total assets	3,356	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	21	21
Other long-term liabilities	0	0
Total liabilities	22	23
Total stockholders’ equity (deficit)	3,334	3,106
Total liabilities and stockholders’ equity (deficit)	3,356	3,129
URNA | Reportable Legal Entities
ASSETS
Cash and cash equivalents	17	23	23	21
Accounts receivable, net	0	56
Intercompany receivable (payable)	(1,200)	(677)
Inventory	94	68
Prepaid expenses and other assets	81	219
Total current assets	(1,008)	(311)
Rental equipment, net	8,243	7,264
Property and equipment, net	394	352
Investments in subsidiaries	1,534	1,148
Goodwill	3,902	3,815
Other intangible assets, net	812	827
Other long-term assets	8	7
Total assets	13,885	13,102
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	28	25
Accounts payable	624	366
Accrued expenses and other liabilities	449	477
Total current liabilities	1,101	868
Long-term debt	9,170	8,596
Deferred taxes	1,518	1,324
Other long-term liabilities	123	120
Total liabilities	11,912	10,908
Total stockholders’ equity (deficit)	1,973	2,194
Total liabilities and stockholders’ equity (deficit)	13,885	13,102
Guarantor Subsidiaries | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany receivable (payable)	(96)	(198)
Inventory	0	0
Prepaid expenses and other assets	0	111
Total current assets	(96)	(87)
Rental equipment, net	0	0
Property and equipment, net	40	32
Investments in subsidiaries	966	1,087
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	910	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	14	17
Total current liabilities	14	17
Long-term debt	9	117
Deferred taxes	0	0
Other long-term liabilities	0	0
Total liabilities	23	134
Total stockholders’ equity (deficit)	887	898
Total liabilities and stockholders’ equity (deficit)	910	1,032
Non-Guarantor Subsidiaries - Foreign | Reportable Legal Entities
ASSETS
Cash and cash equivalents	48	329	301	291
Accounts receivable, net	141	119
Intercompany receivable (payable)	(29)	(124)
Inventory	10	7
Prepaid expenses and other assets	4	2
Total current assets	174	333
Rental equipment, net	667	560
Property and equipment, net	44	42
Investments in subsidiaries	0	0
Goodwill	411	267
Other intangible assets, net	83	48
Other long-term assets	0	0
Total assets	1,379	1,250
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	2	2
Accounts payable	64	43
Accrued expenses and other liabilities	38	41
Total current liabilities	104	86
Long-term debt	3	3
Deferred taxes	89	74
Other long-term liabilities	0	0
Total liabilities	196	163
Total stockholders’ equity (deficit)	1,183	1,087
Total liabilities and stockholders’ equity (deficit)	1,379	1,250
Non-Guarantor Subsidiaries - Domestic | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	1,297	1,058
Intercompany receivable (payable)	0	0
Inventory	0	0
Prepaid expenses and other assets	0	0
Total current assets	1,297	1,058
Rental equipment, net	0	0
Property and equipment, net	0	0
Investments in subsidiaries	22	0
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	1,319	1,058
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	865	695
Accounts payable	0	0
Accrued expenses and other liabilities	2	1
Total current liabilities	867	696
Long-term debt	0	0
Deferred taxes	0	0
Other long-term liabilities	0	0
Total liabilities	867	696
Total stockholders’ equity (deficit)	452	362
Total liabilities and stockholders’ equity (deficit)	1,319	$ 1,058
ABL Facility
Condensed Financial Information Other Details [Abstract]
Line of credit facility, restricted payment capacity	2,034
ABL Facility | URNA
Condensed Financial Information Other Details [Abstract]
Line of credit facility, restricted payment capacity	$ 709
Senior notes | 5 3/4 percent Senior Notes due 2024
Condensed Financial Information Other Details [Abstract]
Stated interest rate	5.75%
URNA | URNA
Condensed Financial Information Other Details [Abstract]
Ownership percentage in subsidiaries	100.00%
URNA | Guarantor Subsidiaries
Condensed Financial Information Other Details [Abstract]
Ownership percentage in subsidiaries	100.00%