Financial Instruments (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Marketable Securities including Strategic Investments
Fair Value	$ 1,812,800,000		$ 1,191,200,000		$ 1,812,800,000
Gross Unrealized Gains	3,100,000		3,500,000		3,100,000
Gross Unrealized Losses	(900,000)		(1,300,000)		(900,000)
Amortized Cost	1,810,600,000		1,189,000,000		1,810,600,000
Summary of financial assets with original maturities of less than 90 days included within cash and cash equivalents
Cash equivalents	440,600,000		651,800,000		440,600,000
Summary of Contractual Maturities: Available-for-Sale Securities
Due in one year or less, Estimated Fair Value	629,200,000		448,100,000		629,200,000
Due in one year or less, Amortized Cost	628,700,000		447,800,000		628,700,000
Due after one year through five years, Estimated Fair Value	1,040,900,000		664,100,000		1,040,900,000
Due after one year through five years, Amortized Cost	1,039,000,000		662,400,000		1,039,000,000
Due after five years, Estimated Fair Value	142,700,000		79,000,000		142,700,000
Due after five years, Amortized Cost	142,900,000		78,800,000		142,900,000
Total available-for-sale securities, Fair Value	1,812,800,000		1,191,200,000		1,812,800,000
Total available-for-sale securities, Amortized Cost	1,810,600,000		1,189,000,000		1,810,600,000
Proceeds from Marketable Securities, excluding Strategic Investments
Proceeds from maturities and sales	381,800,000			973,200,000	1,169,836,000	2,002,543,000
Realized gains	700,000			7,400,000	3,100,000	13,100,000
Realized losses	(500,000)			1,100,000	(1,300,000)	1,800,000
Financial Instruments (Textuals) [Abstract]
Federal Deposit Insurance Corporation guaranteed senior notes issued under the Temporary Liquidity Guarantee Program	247,000,000		163,500,000		247,000,000
Original maturities of commercial paper and short-term debt securities					less than 90 days
Average maturity of marketable securities, months			11 months		13 months
Gain (loss) from sale of strategic equity investments		13,800,000
Impairment charges for publicly - held strategic investments, investments in venture capital funds and investments in privately - held companies	5,500,000			1,200,000	6,800,000	17,000,000
Corporate debt securities Current [Member]
Marketable Securities including Strategic Investments
Fair Value	122,300,000		93,200,000		122,300,000
Gross Unrealized Gains	200,000		100,000		200,000
Gross Unrealized Losses	0		0		0
Amortized Cost	122,100,000		93,100,000		122,100,000
Summary of Contractual Maturities: Available-for-Sale Securities
Total available-for-sale securities, Fair Value	122,300,000		93,200,000		122,300,000
Corporate debt securities Non-current [Member]
Marketable Securities including Strategic Investments
Fair Value	352,800,000		219,800,000		352,800,000
Gross Unrealized Gains	1,300,000		2,100,000		1,300,000
Gross Unrealized Losses	(200,000)		(500,000)		(200,000)
Amortized Cost	351,700,000		218,200,000		351,700,000
Summary of Contractual Maturities: Available-for-Sale Securities
Total available-for-sale securities, Fair Value	352,800,000		219,800,000		352,800,000
Government securities Current [Member]
Marketable Securities including Strategic Investments
Fair Value	504,700,000		352,800,000		504,700,000
Gross Unrealized Gains	300,000		200,000		300,000
Gross Unrealized Losses	0		0		0
Amortized Cost	504,400,000		352,600,000		504,400,000
Summary of Contractual Maturities: Available-for-Sale Securities
Total available-for-sale securities, Fair Value	504,700,000		352,800,000		504,700,000
Government securities Non-current [Member]
Marketable Securities including Strategic Investments
Fair Value	590,700,000		432,500,000		590,700,000
Gross Unrealized Gains	800,000		600,000		800,000
Gross Unrealized Losses	(100,000)		(600,000)		(100,000)
Amortized Cost	590,000,000		432,500,000		590,000,000
Summary of Contractual Maturities: Available-for-Sale Securities
Total available-for-sale securities, Fair Value	590,700,000		432,500,000		590,700,000
Mortgage and other asset backed securities Current [Member]
Marketable Securities including Strategic Investments
Fair Value	2,200,000		2,100,000		2,200,000
Gross Unrealized Gains	0		0		0
Gross Unrealized Losses	0		0		0
Amortized Cost	2,200,000		2,100,000		2,200,000
Summary of Contractual Maturities: Available-for-Sale Securities
Total available-for-sale securities, Fair Value	2,200,000		2,100,000		2,200,000
Mortgage and other asset backed securities Non-current [Member]
Marketable Securities including Strategic Investments
Fair Value	240,100,000		90,800,000		240,100,000
Gross Unrealized Gains	500,000		500,000		500,000
Gross Unrealized Losses	(600,000)		(200,000)		(600,000)
Amortized Cost	240,200,000		90,500,000		240,200,000
Summary of Contractual Maturities: Available-for-Sale Securities
Total available-for-sale securities, Fair Value	240,100,000		90,800,000		240,100,000
Other strategic investments Non-current [Member]
Marketable Securities including Strategic Investments
Gross Unrealized Gains	500,000		17,500,000		500,000
Gross Unrealized Losses	0		0		0
Amortized Cost	1,500,000		27,300,000		1,500,000
Strategic investments, non-current Fair Value	2,000,000		44,800,000		2,000,000
Commercial Paper [Member]
Summary of financial assets with original maturities of less than 90 days included within cash and cash equivalents
Cash equivalents	8,000,000		4,000,000		8,000,000
Repurchase Agreements [Member]
Summary of financial assets with original maturities of less than 90 days included within cash and cash equivalents
Cash equivalents	80,900,000		26,000,000		80,900,000
Debt Securities [Member]
Summary of financial assets with original maturities of less than 90 days included within cash and cash equivalents
Cash equivalents	$ 351,700,000		$ 621,800,000		$ 351,700,000