Restructuring and Asset Impairment Charges (Narrative) (Details) (USD $) In Millions, unless otherwise specified				3 Months Ended	9 Months Ended
Sep. 30, 2013 employees Locations	Dec. 31, 2011 Locations employees	Dec. 31, 2007 employees Locations	Sep. 30, 2013 General rentals [Member]	Sep. 30, 2012 General rentals [Member]	Sep. 30, 2013 General rentals [Member]	Sep. 30, 2012 General rentals [Member]
Restructuring Cost and Reserve [Line Items]
Employee headcount	11,700	7,500	10,900
Number of locations	822	529	697
Asset impairment charges				$ 0	$ 10	$ 4	$ 13

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2420-110228

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration