Goodwill And Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Goodwill	$ 1,172.2		$ 1,172.2		$ 1,172.2
Franchise rights - indefinite-lived	208.4		208.4		212.6
Other intangibles	8.4		8.4		8.4
Intangible Assets Gross (Excluding Goodwill)	216.8		216.8		221.0
Less: accumulated amortization	(3.8)		(3.8)		(3.2)
Other intangible assets, net	213.0		213.0		217.8
Franchise rights impairment	4.2	0	4.2	0
Franchise Rights [Member]
Date of annual goodwill and indefinite lived intangible assets impairment test			April 30
Franchise rights impairment	4.2	0	4.2	0
Franchise rights impairment, net of tax			$ 2.6
Goodwill [Member]
Date of annual goodwill and indefinite lived intangible assets impairment test			April 30