Fair Value Measurements, Assets and Liabilities Measured On A Nonrecurring Basis (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost-method Investments, Realized Gain (Loss)	$ 5.8	$ (1.1)	$ 6.6	$ (1.0)
Privately-held investments measured on nonrecurring basis	33.9		33.9		51.8
Other than temporary impairment of privately held equity investments measured on a non-recurring basis	6.0	1.8	20.0	1.8
Fair Value Liabilities Measured On Nonrecurring Basis Liabilities	0		0		0
Fair Value of Cost Method Investments Subsequent to Impairment	0		0
Carrying Value of Intangible Assets	5.4		5.4
Fair Value of Intangible Asset Subsequent to Impairment	0		0
Other than temporary impairment of intangible assets	5.4	0	5.4	0
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Privately-held investments measured on nonrecurring basis	6.0		6.0		0.4
Carrying Value of Intangible Assets	$ 5.4		$ 5.4		$ 0