Description of Business and Summary of Significant Accounting Policies (Goodwill and Other Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Goodwill and Intangible Assets [Line Items]
Franchise agreements, minimal contractual terms (in years)	1 year
Goodwill impairment	$ 0	$ 0	$ 0
Franchise rights impairment	4.2	0	0
Maximum [Member]
Goodwill and Intangible Assets [Line Items]
Other intangibles, useful life	29 years
Minimum [Member]
Goodwill and Intangible Assets [Line Items]
Other intangibles, useful life	3 years
Nonrecurring [Member] | Franchise rights [Member]
Goodwill and Intangible Assets [Line Items]
Franchise rights impairment	4.2	0	0
Franchise rights impairment, after tax	$ 2.6