Condensed Consolidating Financial Information of Guarantor Subsidiaries - CONDENSED CONSOLIDATING BALANCE SHEETS (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Cash and cash equivalents	$ 43	$ 352	$ 312	$ 179
Accounts receivable, net	1,545	1,233
Intercompany receivable (payable)	0	0
Inventory	109	75
Prepaid expenses and other assets	64	112
Total current assets	1,761	1,772
Rental equipment, net	9,600	7,824
Property and equipment, net	614	467
Investments in subsidiaries	0	0
Goodwill	5,058	4,082	3,260	3,243
Other intangible assets, net	1,084	875
Other long-term assets	16	10
Total assets	18,133	15,030	11,988
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	903	723
Accounts payable	536	409
Accrued expenses and other liabilities	677	536
Total current liabilities	2,116	1,668
Long-term debt	10,844	8,717
Deferred taxes	1,687	1,419
Other long-term liabilities	83	120
Total liabilities	14,730	11,924
Total stockholders’ equity (deficit)	3,403	3,106
Total liabilities and stockholders’ equity	18,133	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	(4,452)	(4,429)
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	(4,452)	(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)	(4,452)	(4,541)
Total liabilities and stockholders’ equity	(4,452)	(4,541)
Parent | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany receivable (payable)	1,534	887
Inventory	0	0
Prepaid expenses and other assets	0	4
Total current assets	1,534	891
Rental equipment, net	0	0
Property and equipment, net	57	41
Investments in subsidiaries	1,826	2,194
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	9	3
Total assets	3,426	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)	3,403	3,106
Total liabilities and stockholders’ equity	3,426	3,129
URNA | Reportable Legal Entities
ASSETS
Cash and cash equivalents	1	23	21	18
Accounts receivable, net	0	56
Intercompany receivable (payable)	(1,423)	(677)
Inventory	96	68
Prepaid expenses and other assets	60	219
Total current assets	(1,266)	(311)
Rental equipment, net	8,910	7,264
Property and equipment, net	462	352
Investments in subsidiaries	1,646	1,148
Goodwill	4,661	3,815
Other intangible assets, net	1,004	827
Other long-term assets	7	7
Total assets	15,424	13,102
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	50	25
Accounts payable	481	366
Accrued expenses and other liabilities	619	477
Total current liabilities	1,150	868
Long-term debt	10,778	8,596
Deferred taxes	1,587	1,324
Other long-term liabilities	83	120
Total liabilities	13,598	10,908
Total stockholders’ equity (deficit)	1,826	2,194
Total liabilities and stockholders’ equity	15,424	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	980	1,087
Goodwill	0	0
Other intangible assets, net	0	0
Other long-term assets	0	0
Total assets	924	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)	901	898
Total liabilities and stockholders’ equity	924	1,032
Foreign | Reportable Legal Entities
ASSETS
Cash and cash equivalents	42	329	291	161
Accounts receivable, net	159	119
Intercompany receivable (payable)	(15)	(124)
Inventory	13	7
Prepaid expenses and other assets	4	2
Total current assets	203	333
Rental equipment, net	690	560
Property and equipment, net	55	42
Investments in subsidiaries	0	0
Goodwill	397	267
Other intangible assets, net	80	48
Other long-term assets	0	0
Total assets	1,425	1,250
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	2	2
Accounts payable	55	43
Accrued expenses and other liabilities	42	41
Total current liabilities	99	86
Long-term debt	57	3
Deferred taxes	78	74
Other long-term liabilities	0	0
Total liabilities	234	163
Total stockholders’ equity (deficit)	1,191	1,087
Total liabilities and stockholders’ equity	1,425	1,250
SPV | Reportable Legal Entities
ASSETS
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	1,386	1,058
Intercompany receivable (payable)	0	0
Inventory	0	0
Prepaid expenses and other assets	0	0
Total current assets	1,386	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	1,386	1,058
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	850	695
Accounts payable	0	0
Accrued expenses and other liabilities	2	1
Total current liabilities	852	696
Long-term debt	0	0
Deferred taxes	0	0
Other long-term liabilities	0	0
Total liabilities	852	696
Total stockholders’ equity (deficit)	534	362
Total liabilities and stockholders’ equity	1,386	$ 1,058
ABL facility
Condensed Financial Information Other Details [Abstract]
Line of credit facility, restricted payment capacity	2,117
ABL facility | URNA
Condensed Financial Information Other Details [Abstract]
Line of credit facility, restricted payment capacity	$ 583
Senior notes | 5 3/4 percent Senior Notes due 2024
Condensed Financial Information Other Details [Abstract]
Stated interest rate	5.75%