Fair Value Measurements Impairment losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Gain (loss) on sale or impairment of long lived assets, net	$ (0.1)	$ (5.5)
Fair Value, Inputs, Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Impairment charge of assets no longer used		3.6
Impairment of Long-Lived Assets Held-for-use		$ 1.9