Fair Value Measurements, Assets and Liabilities Measured On A Nonrecurring Basis (Details) (USD $)	3 Months Ended							3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2011 Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2012 Cost Method Investee, Privately Held Companies	Dec. 31, 2011 Cost Method Investee, Privately Held Companies	Mar. 31, 2012 Cost Method Investee, Privately Held Companies Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2011 Cost Method Investee, Privately Held Companies Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2012 Cost Method Investee, Privately Held Companies Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2011 Cost Method Investee, Privately Held Companies Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments measured on nonrecurring basis				$ 36,000,000	$ 51,800,000	$ 6,000,000	$ 400,000
Loss due to impairment of privately held equity investments measured on a non-recurring basis	14,000,000							14,000,000	0
Fair Value Liabilities Measured On Nonrecurring Basis Liabilities		$ 0	$ 0