Goodwill and Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 1,237.4	[1]	$ 1,172.2	[1]	$ 1,142.4	[1]
Franchise rights - indefinite-lived	285.7		212.6
Other intangibles	9.9		8.4
Intangible assets, gross	295.6		221.0
Less: accumulated amortization	(4.3)		(3.2)
Intangible assets, net	$ 291.3		$ 217.8

[1] Net of accumulated impairment losses of $1.47 billion ($1.25 billion after-tax) associated with our single reporting unit (prior to September 30, 2008, our reporting unit structure was comprised of a single reporting unit) and $140.0 million ($119.0 million after-tax) associated with our Domestic reporting unit, both of which were recorded during the year ended December 31, 2008.