Cash, Cash Equivalents, and Investments - Textuals (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended						12 Months Ended							12 Months Ended
	Dec. 31, 2011 month investments	Dec. 31, 2010 investments	Dec. 31, 2009	Apr. 08, 2010	Jun. 30, 2010 Business Acquisition Acquired Entity Ankeena [Member]	Jun. 30, 2010 Business Acquisition Acquired Entity Altor [Member]	Dec. 31, 2011 Cost Method Investee, Privately Held Companies	Dec. 31, 2010 Cost Method Investee, Privately Held Companies	Dec. 31, 2009 Cost Method Investee, Privately Held Companies	Dec. 31, 2010 Cost Method Investee, Privately Held Companies Business Acquisition Acquired Entity Ankeena [Member]	Dec. 31, 2010 Cost Method Investee, Privately Held Companies Business Acquisition Acquired Entity Altor [Member]	Dec. 31, 2011 Fair Value, Measurements, Nonrecurring [Member] Cost Method Investee, Privately Held Companies	Dec. 31, 2010 Fair Value, Measurements, Nonrecurring [Member] Cost Method Investee, Privately Held Companies	Dec. 31, 2011 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Cost Method Investee, Privately Held Companies	Dec. 31, 2010 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Cost Method Investee, Privately Held Companies	Dec. 31, 2009 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member] Cost Method Investee, Privately Held Companies
Equity Method Investments					$ 2.0	$ 2.0
Proceeds from Sale and Maturity of Marketable Securities	1,926.6	1,624.4	683.8
Total investments In unrealized loss position	135	73
Decrease in Restricted Cash	42.0
Increase in restricted cash		261.9
Restricted Cash Distribution For Settlement Of Acquisition		196.5
Business Acquisition, Cash Value of Unvested Restricted Shares	0.9			10.7
Vesting Period For Restricted Shares (in months)	9
Business Acquisition, Payments for Restricted Shares That Have Vested	9.8
Minority equity investment							51.8	22.1				0.4	0.8
Investment in privately-held companies							33.1	13.3	7.2
Cost-method Investments, Realized Gains										3.2	2.1
Cost Method Investment, Other than Temporary Impairment														$ 1.8	$ 0	$ 5.5