Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2011

Fair Value Measurements [Abstract]

Summary Of Assets And Liabilities Recorded At Fair Value

	September 30, 2011								December 31, 2010
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets:
Debt securities:
U.S. treasury securities	$	1,155,328	$	—	$	—	$	1,155,328	$	1,355,437	$	—	$	—	$	1,355,437
Money market funds		372,260		—		—		372,260		520,063		—		—		520,063
U.S. government agencies and FDIC guaranteed securities		—		1,090,587		—		1,090,587		—		1,296,110		—		1,296,110
Municipal debt securities		—		24,591		—		24,591		—		17,625		—		17,625
Non-U.S. government securities		—		211,764		25,314		237,078		—		278,610		9,594		288,204
Corporate debt securities		—		1,703,869		—		1,703,869		—		1,119,254		—		1,119,254
Residential mortgage and asset-backed securities		—		316,526		—		316,526		—		277,043		—		277,043
Student loan-backed securities		—		—		56,507		56,507		—		—		70,771		70,771
Total debt securities		1,527,588		3,347,337		81,821		4,956,746		1,875,500		2,988,642		80,365		4,944,507
Equity securities		5,267		—		—		5,267		4,631		—		—		4,631
Derivatives		—		46,229		—		46,229		—		64,461		—		64,461
	$	1,532,855	$	3,393,566	$	81,821	$	5,008,242	$	1,880,131	$	3,053,103	$	80,365	$	5,013,599
Liabilities:
Contingent consideration	$	—	$	—	$	128,305	$	128,305	$	—	$	—	$	11,100	$	11,100
Derivatives		—		39,119		—		39,119		—		38,553		—		38,553
	$	—	$	39,119	$	128,305	$	167,424	$	—	$	38,553	$	11,100	$	49,653

Reconciliation Of Marketable Securities Measured At Fair Value Using Significant Unobservable Inputs (Level 3)

	Three Months Ended September 30,						Nine Months Ended September 30,
	2011			2010			2011			2010
Balance, beginning of period	$	104,145		$	94,062		$	80,365		$	105,662
Total realized and unrealized gains (losses) included in:
Interest and other income, net		1,707			—			4,578			115
Other comprehensive income, net		(22,681	)		2,299			(28,375	)		4,066
Sales of marketable securities		(1,350	)		(8,050	)		(28,630	)		(21,532	)
Transfers into Level 3		—			—			53,883			—
Balance, end of period	$	81,821		$	88,311		$	81,821		$	88,311
Total losses included in interest and other income, net attributable to the change in unrealized losses relating to assets still held at the reporting date	$	—		$	—		$	—		$	—