Fair Value Hierarchy For Financial Assets And Liabilities Measured At Fair Value (Detail) (USD $)	Mar. 31, 2012
Total cash and investments	$ 10,878,543,000
Convertible debt	(3,191,887,000)
Foreign exchange derivative assets	42,778,000
Foreign exchange derivative liabilities	(32,291,000)
Cash
Total cash and investments	1,821,521,000
Cash Equivalents
Total cash and investments	2,849,654,000
US Government Agencies Debt Securities
Total cash and investments	2,220,532,000
US Corporate Debt Securities
Total cash and investments	1,382,071,000
High Yield Corporate Debt Securities
Total cash and investments	469,349,000
Asset-backed Securities
Total cash and investments	42,856,000
Municipal Obligations
Total cash and investments	899,980,000
Auction Rate Securities
Total cash and investments	78,397,000
Foreign Debt Securities
Total cash and investments	1,032,614,000
Publicly Traded Equity Securities
Total cash and investments	81,569,000
Strategic Investments Held At Cost
Total cash and investments	203,847,000
Commodity Contract
Commodity derivative liabilities	(5,410,000)
Interest Rate Swap
Commodity derivative liabilities	(3,831,000)
Fair Value, Inputs, Level 1
Total cash and investments	5,829,604,000
Fair Value, Inputs, Level 1 | Cash
Total cash and investments	1,821,521,000
Fair Value, Inputs, Level 1 | Cash Equivalents
Total cash and investments	2,796,165,000
Fair Value, Inputs, Level 1 | US Government Agencies Debt Securities
Total cash and investments	1,130,349,000
Fair Value, Inputs, Level 1 | Publicly Traded Equity Securities
Total cash and investments	81,569,000
Fair Value, Inputs, Level 2
Total cash and investments	4,970,542,000
Convertible debt	(3,191,887,000)
Foreign exchange derivative assets	42,778,000
Foreign exchange derivative liabilities	(32,291,000)
Fair Value, Inputs, Level 2 | Cash Equivalents
Total cash and investments	53,489,000
Fair Value, Inputs, Level 2 | US Government Agencies Debt Securities
Total cash and investments	1,090,183,000
Fair Value, Inputs, Level 2 | US Corporate Debt Securities
Total cash and investments	1,382,071,000
Fair Value, Inputs, Level 2 | High Yield Corporate Debt Securities
Total cash and investments	469,349,000
Fair Value, Inputs, Level 2 | Asset-backed Securities
Total cash and investments	42,856,000
Fair Value, Inputs, Level 2 | Municipal Obligations
Total cash and investments	899,980,000
Fair Value, Inputs, Level 2 | Foreign Debt Securities
Total cash and investments	1,032,614,000
Fair Value, Inputs, Level 2 | Commodity Contract
Commodity derivative liabilities	(5,410,000)
Fair Value, Inputs, Level 2 | Interest Rate Swap
Commodity derivative liabilities	(3,831,000)
Fair Value, Inputs, Level 3
Total cash and investments	78,397,000
Fair Value, Inputs, Level 3 | Auction Rate Securities
Total cash and investments	78,397,000
Fair Value, Inputs, Level 3 | Strategic Investments Held At Cost
Total cash and investments	$ 203,847,000