Condensed Consolidating Financial Information of Guarantor Subsidiaries - CONDENSED CONSOLIDATING BALANCE SHEETS (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 158		$ 175		$ 106		$ 36
Accounts receivable, net	940		804
Intercompany receivable (payable)	0		0
Inventory	78		70
Prepaid expenses and other assets	122		53
Deferred taxes	248		260
Total current assets	1,546		1,362
Investments in subsidiaries	0		0
Goodwill	3,272	[1]	2,953	[1]	2,970	[1]	289	[1]
Other intangible assets, net	1,106		1,018
Other long-term assets	97		103
Total assets (1)	12,467	[2]	11,231	[2]
LIABILITIES AND STOCKHOLDERS’ EQUITY
Short-term debt and current maturities of long-term debt	618		604
Accounts payable	285		292
Accrued expenses and other liabilities	575		390
Total current liabilities	1,478		1,286
Long-term debt	7,434		6,569
Deferred taxes	1,692		1,459
Other long-term liabilities	65		69
Total liabilities	10,669		9,383
Temporary equity (note 12)	2		20
Total stockholders’ equity (deficit)	1,796		1,828
Total liabilities and stockholders’ equity	12,467		11,231
Eliminations
ASSETS
Cash and cash equivalents	0		0		0		0
Accounts receivable, net	0		0
Intercompany receivable (payable)	121		132
Inventory	0		0
Prepaid expenses and other assets	0		0
Deferred taxes	0		0
Total current assets	121		132
Investments in subsidiaries	(3,555)		(3,777)
Goodwill	0		0
Other intangible assets, net	0		0
Other long-term assets	0		0
Total assets (1)	(3,434)		(3,645)
LIABILITIES AND STOCKHOLDERS’ EQUITY
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 (note 12)	0		0
Total stockholders’ equity (deficit)	(3,434)		(3,645)
Total liabilities and stockholders’ equity	(3,434)		(3,645)
Parent
ASSETS
Cash and cash equivalents	0		0		0		0
Accounts receivable, net	0		0
Intercompany receivable (payable)	476		308
Inventory	0		0
Prepaid expenses and other assets	0		0
Deferred taxes	0		0
Total current assets	476		308
Investments in subsidiaries	1,330		1,648
Goodwill	0		0
Other intangible assets, net	0		0
Other long-term assets	1		2
Total assets (1)	1,849		2,006
LIABILITIES AND STOCKHOLDERS’ EQUITY
Short-term debt and current maturities of long-term debt	32		136
Accounts payable	0		0
Accrued expenses and other liabilities	0		1
Total current liabilities	32		137
Long-term debt	0		0
Deferred taxes	19		21
Other long-term liabilities	0		0
Total liabilities	51		158
Temporary equity (note 12)	2		20
Total stockholders’ equity (deficit)	1,796		1,828
Total liabilities and stockholders’ equity	1,849		2,006
URNA
Condensed Financial Information Other Details [Abstract]
Ownership percentage in subsidiaries	100.00%
ASSETS
Cash and cash equivalents	8		17		20		6
Accounts receivable, net	37		36
Intercompany receivable (payable)	(428)		(257)
Inventory	69		62
Prepaid expenses and other assets	113		42
Deferred taxes	246		258
Total current assets	45		158
Investments in subsidiaries	1,185		1,132
Goodwill	3,000		2,708
Other intangible assets, net	1,014		931
Other long-term assets	96		100
Total assets (1)	11,071		10,110
LIABILITIES AND STOCKHOLDERS’ EQUITY
Short-term debt and current maturities of long-term debt	38		38
Accounts payable	248		254
Accrued expenses and other liabilities	499		327
Total current liabilities	785		619
Long-term debt	7,298		6,421
Deferred taxes	1,594		1,357
Other long-term liabilities	64		65
Total liabilities	9,741		8,462
Temporary equity (note 12)	0		0
Total stockholders’ equity (deficit)	1,330		1,648
Total liabilities and stockholders’ equity	11,071		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)	(60)		(51)
Inventory	0		0
Prepaid expenses and other assets	1		1
Deferred taxes	0		0
Total current assets	(59)		(50)
Investments in subsidiaries	1,040		997
Goodwill	0		0
Other intangible assets, net	0		0
Other long-term assets	0		0
Total assets (1)	1,002		967
LIABILITIES AND STOCKHOLDERS’ EQUITY
Short-term debt and current maturities of long-term debt	0		0
Accounts payable	0		0
Accrued expenses and other liabilities	19		25
Total current liabilities	19		25
Long-term debt	130		140
Deferred taxes	0		0
Other long-term liabilities	0		0
Total liabilities	149		165
Temporary equity (note 12)	0		0
Total stockholders’ equity (deficit)	853		802
Total liabilities and stockholders’ equity	1,002		967
Non Guarantor Subsidiaries - Foreign
ASSETS
Cash and cash equivalents	150		158		86		30
Accounts receivable, net	144		140
Intercompany receivable (payable)	(109)		(132)
Inventory	9		8
Prepaid expenses and other assets	8		10
Deferred taxes	2		2
Total current assets	204		186
Investments in subsidiaries	0		0
Goodwill	272		245
Other intangible assets, net	92		87
Other long-term assets	0		0
Total assets (1)	1,220		1,164
LIABILITIES AND STOCKHOLDERS’ EQUITY
Short-term debt and current maturities of long-term debt	0		0
Accounts payable	37		38
Accrued expenses and other liabilities	57		36
Total current liabilities	94		74
Long-term debt	6		8
Deferred taxes	79		81
Other long-term liabilities	1		4
Total liabilities	180		167
Temporary equity (note 12)	0		0
Total stockholders’ equity (deficit)	1,040		997
Total liabilities and stockholders’ equity	1,220		1,164
Non Guarantor Subsidiaries - SPV
ASSETS
Cash and cash equivalents	0		0		0		0
Accounts receivable, net	759		628
Intercompany receivable (payable)	0		0
Inventory	0		0
Prepaid expenses and other assets	0		0
Deferred taxes	0		0
Total current assets	759		628
Investments in subsidiaries	0		0
Goodwill	0		0
Other intangible assets, net	0		0
Other long-term assets	0		1
Total assets (1)	759		629
LIABILITIES AND STOCKHOLDERS’ EQUITY
Short-term debt and current maturities of long-term debt	548		430
Accounts payable	0		0
Accrued expenses and other liabilities	0		1
Total current liabilities	548		431
Long-term debt	0		0
Deferred taxes	0		0
Other long-term liabilities	0		0
Total liabilities	548		431
Temporary equity (note 12)	0		0
Total stockholders’ equity (deficit)	211		198
Total liabilities and stockholders’ equity	759		629
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	242
Rental equipment, net
ASSETS
Property, plant and equipment, net	6,008		5,374
Rental equipment, net | Eliminations
ASSETS
Property, plant and equipment, net	0		0
Rental equipment, net | Parent
ASSETS
Property, plant and equipment, net	0		0
Rental equipment, net | URNA
ASSETS
Property, plant and equipment, net	5,399		4,768
Rental equipment, net | Guarantor Subsidiaries
ASSETS
Property, plant and equipment, net	0		0
Rental equipment, net | Non Guarantor Subsidiaries - Foreign
ASSETS
Property, plant and equipment, net	609		606
Rental equipment, net | Non Guarantor Subsidiaries - SPV
ASSETS
Property, plant and equipment, net	0		0
Property and equipment, net
ASSETS
Property, plant and equipment, net	438		421
Property and equipment, net | Eliminations
ASSETS
Property, plant and equipment, net	0		0
Property and equipment, net | Parent
ASSETS
Property, plant and equipment, net	42		48
Property and equipment, net | URNA
ASSETS
Property, plant and equipment, net	332		313
Property and equipment, net | Guarantor Subsidiaries
ASSETS
Property, plant and equipment, net	21		20
Property and equipment, net | Non Guarantor Subsidiaries - Foreign
ASSETS
Property, plant and equipment, net	43		40
Property and equipment, net | Non Guarantor Subsidiaries - SPV
ASSETS
Property, plant and equipment, net	$ 0		$ 0

[1] The total carrying amount of goodwill for all periods in the table above is reflected net of $1,557 of accumulated impairment charges, which were primarily recorded in our general rentals segment.

[2] The increase in the trench safety, power and HVAC, and pump solutions assets in 2014 primarily reflects the impact of the National Pump acquisition discussed in note 3 to the consolidated financial statements.