Commitments and Contingencies (Capital Lease Obligations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Commitments and Contingencies Disclosure [Abstract]
Debt and capital lease obligations	$ 7,309	[1]	$ 2,987	[1]
Capital Leased Assets [Line Items]
Depreciation of rental equipment	699		423		389
Non-rental depreciation and amortization	198		57		60
Less accumulated depreciation and amortization	(9)		(13)
Property and equipment, net	31		13
Rental Equipment [Member]
Capital Leased Assets [Line Items]
Depreciation of rental equipment	15		3		6
Property and equipment	167		51
Less accumulated depreciation and amortization	(23)		24
Property and equipment, net	144		27
Non Rental Equipment [Member]
Capital Leased Assets [Line Items]
Non-rental depreciation and amortization	4		4		4
Non-rental vehicles [Member]
Capital Leased Assets [Line Items]
Property and equipment	23		9
Buildings [Member]
Capital Leased Assets [Line Items]
Property and equipment	$ 17		$ 17

[1] In August 1998, a subsidiary trust of Holdings (the “Trust”) issued and sold $300 of 6 1/2 percent Convertible Quarterly Income Preferred Securities (“QUIPS”) in a private offering. The Trust used the proceeds from the offering to purchase 6 1/2 percent subordinated convertible debentures due 2028 (the “Debentures”), which resulted in Holdings receiving all of the net proceeds of the offering. The QUIPS are non-voting securities, carry a liquidation value of $50 (fifty dollars) per security and are convertible into Holdings’ common stock. Total long-term debt at December 31, 2012 and 2011 excludes $55 of these Debentures, which are separately classified in our consolidated balance sheets and referred to as “subordinated convertible debentures.” The subordinated convertible debentures reflect the obligation to our subsidiary that has issued the QUIPS. This subsidiary is not consolidated in our financial statements because we are not the primary beneficiary of the Trust. See note 13 (“Subordinated Convertible Debentures”) for additional detail.