Condensed Consolidating Financial Information of Guarantor Subsidiaries CONDENSED CONSOLIDATING BALANCE SHEET (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013		Mar. 31, 2013	Dec. 31, 2012
Condensed Financial Information Other Details [Abstract]
Stated interest rate	4.00%
ASSETS
Cash and cash equivalents	$ 227		$ 175		$ 147	$ 106
Accounts receivable, net	752		804
Intercompany receivable (payable)	0		0
Inventory	102		70
Prepaid expenses and other assets	59		53
Deferred taxes	260		260
Total current assets	1,400		1,362
Rental equipment, net	5,406		5,374
Property and equipment, net	408		421
Investments in subsidiaries	0		0
Goodwill, net	2,944		2,953
Other intangible assets, net	972		1,018
Other long-term assets	117		103
Total assets	11,247		11,231
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	265	[1]	604	[1]
Accounts payable	454		292
Accrued expenses and other liabilities	382		390
Total current liabilities	1,101		1,286
Long-term debt	6,774		6,569
Deferred taxes	1,481		1,459
Other long-term liabilities	67		69
Total liabilities	9,423		9,383
Temporary equity	11		20
Total stockholders’ equity (deficit)	1,813		1,828
Total liabilities and stockholders’ equity	11,247		11,231
Parent
ASSETS
Cash and cash equivalents	0		0		0	0
Accounts receivable, net	0		0
Intercompany receivable (payable)	261		308
Inventory	0		0
Prepaid expenses and other assets	0		0
Deferred taxes	0		0
Total current assets	261		308
Rental equipment, net	0		0
Property and equipment, net	46		48
Investments in subsidiaries	1,629		1,648
Goodwill, net	0		0
Other intangible assets, net	0		0
Other long-term assets	1		2
Total assets	1,937		2,006
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	89		136
Accounts payable	0		0
Accrued expenses and other liabilities	2		1
Total current liabilities	91		137
Long-term debt	0		0
Deferred taxes	22		21
Other long-term liabilities	0		0
Total liabilities	113		158
Temporary equity	11		20
Total stockholders’ equity (deficit)	1,813		1,828
Total liabilities and stockholders’ equity	1,937		2,006
URNA
Condensed Financial Information Other Details [Abstract]
Ownership percentage in subsidiaries	100.00%
ASSETS
Cash and cash equivalents	23		17		24	20
Accounts receivable, net	37		36
Intercompany receivable (payable)	(199)		(257)
Inventory	92		62
Prepaid expenses and other assets	48		42
Deferred taxes	258		258
Total current assets	259		158
Rental equipment, net	4,838		4,768
Property and equipment, net	302		313
Investments in subsidiaries	1,372		1,132
Goodwill, net	2,708		2,708
Other intangible assets, net	892		931
Other long-term assets	116		100
Total assets	10,487		10,110
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	36		38
Accounts payable	413		254
Accrued expenses and other liabilities	329		327
Total current liabilities	778		619
Long-term debt	6,632		6,421
Deferred taxes	1,381		1,357
Other long-term liabilities	67		65
Total liabilities	8,858		8,462
Temporary equity	0		0
Total stockholders’ equity (deficit)	1,629		1,648
Total liabilities and stockholders’ equity	10,487		10,110
Guarantor Subsidiaries
Condensed Financial Information Other Details [Abstract]
Ownership percentage in subsidiaries	100.00%
ASSETS
Cash and cash equivalents	0		0		0	0
Accounts receivable, net	0		0
Intercompany receivable (payable)	(55)		(51)
Inventory	0		0
Prepaid expenses and other assets	2		1
Deferred taxes	0		0
Total current assets	(53)		(50)
Rental equipment, net	0		0
Property and equipment, net	20		20
Investments in subsidiaries	984		997
Goodwill, net	0		0
Other intangible assets, net	0		0
Other long-term assets	0		0
Total assets	951		967
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	21		25
Total current liabilities	21		25
Long-term debt	135		140
Deferred taxes	0		0
Other long-term liabilities	0		0
Total liabilities	156		165
Temporary equity	0		0
Total stockholders’ equity (deficit)	795		802
Total liabilities and stockholders’ equity	951		967
Non Guarantor Subsidiaries Foreign
ASSETS
Cash and cash equivalents	204		158		123	86
Accounts receivable, net	126		140
Intercompany receivable (payable)	(135)		(132)
Inventory	10		8
Prepaid expenses and other assets	9		10
Deferred taxes	2		2
Total current assets	216		186
Rental equipment, net	568		606
Property and equipment, net	40		40
Investments in subsidiaries	0		0
Goodwill, net	236		245
Other intangible assets, net	80		87
Other long-term assets	0		0
Total assets	1,140		1,164
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	0		0
Accounts payable	41		38
Accrued expenses and other liabilities	30		36
Total current liabilities	71		74
Long-term debt	7		8
Deferred taxes	78		81
Other long-term liabilities	0		4
Total liabilities	156		167
Temporary equity	0		0
Total stockholders’ equity (deficit)	984		997
Total liabilities and stockholders’ equity	1,140		1,164
Non Guarantor Subsidiaries SPV
ASSETS
Cash and cash equivalents	0		0		0	0
Accounts receivable, net	589		628
Intercompany receivable (payable)	0		0
Inventory	0		0
Prepaid expenses and other assets	0		0
Deferred taxes	0		0
Total current assets	589		628
Rental equipment, net	0		0
Property and equipment, net	0		0
Investments in subsidiaries	0		0
Goodwill, net	0		0
Other intangible assets, net	0		0
Other long-term assets	0		1
Total assets	589		629
LIABILITIES AND STOCKHOLDERS’ EQUITY (DEFICIT)
Short-term debt and current maturities of long-term debt	140		430
Accounts payable	0		0
Accrued expenses and other liabilities	0		1
Total current liabilities	140		431
Long-term debt	0		0
Deferred taxes	0		0
Other long-term liabilities	0		0
Total liabilities	140		431
Temporary equity	0		0
Total stockholders’ equity (deficit)	449		198
Total liabilities and stockholders’ equity	589		629
Eliminations
ASSETS
Cash and cash equivalents	0		0		0	0
Accounts receivable, net	0		0
Intercompany receivable (payable)	128		132
Inventory	0		0
Prepaid expenses and other assets	0		0
Deferred taxes	0		0
Total current assets	128		132
Rental equipment, net	0		0
Property and equipment, net	0		0
Investments in subsidiaries	(3,985)		(3,777)
Goodwill, net	0		0
Other intangible assets, net	0		0
Other long-term assets	0		0
Total assets	(3,857)		(3,645)
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
Temporary equity	0		0
Total stockholders’ equity (deficit)	(3,857)		(3,645)
Total liabilities and stockholders’ equity	(3,857)		(3,645)
10 1/4 percent Senior Notes
Condensed Financial Information Other Details [Abstract]
Stated interest rate	10.25%
8 1/4 percent Senior Notes
Condensed Financial Information Other Details [Abstract]
Stated interest rate	8.25%
ABL Facility, Accounts Receivable Securitization Facility, and Other Agreements | URNA
Condensed Financial Information Other Details [Abstract]
Line of credit facility, restricted payment capacity	$ 448

[1] As of March 31, 2014, our short-term debt primarily reflects $140 of borrowings under our accounts receivable securitization facility and $89 of 4 percent Convertible Senior Notes. The 4 percent Convertible Senior Notes mature in November 2015, but are reflected as short-term debt because they are redeemable at March 31, 2014.