Fair Value Measurements Impairment losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2011 Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2011 Fair Value, Inputs, Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Asset Impairment Charges		$ 62.0
Impairment charge of assets no longer used	4.4		2.4	3.6
Impairment of Long-Lived Assets Held-for-use			$ 0.5	$ 4.4