Commitments And Contingencies (Narrative) (Details) (USD $)	12 Months Ended
Dec. 31, 2012 signs	Dec. 31, 2011	Dec. 31, 2010
Maximum aggregate contingency subject to performance requirements of the seller	$ 30,000,000
Rent expense	1,140,000,000	1,160,000,000	1,100,000,000
Payment of income tax expense due to settlement	$ 10,900,000
Static signs converted to digital	83

Rent expense for each period for which an income statement is presented for minimum lease payments, contingent rentals, and sublease rentals.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 16

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 13

-Paragraph 122

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_OperatingLeasesRentExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration