Fair Value of Financial Assets and Liabilities - Fair Value Hierarchy For Financial Assets And Liabilities Measured At Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	$ 11,395,728	$ 10,843,129
Investment in joint venture	32,745
Cash
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,493,843	3,096,275
Cash equivalents
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	3,260,217	1,434,761
U.S. government and agency obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	2,196,209	2,484,961
U.S. corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,480,450	1,407,753
High yield corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	510,412	447,479
Asset-backed securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	2,117	29,148
Municipal obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,022,889	816,081
Commodity derivative liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities	(588)	(3,093)
Auction rate securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	70,086	74,596
Foreign debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,273,023	987,074
Publicly traded equity securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	86,482	65,001
Strategic investments held at cost
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	351,855
Convertible debt
Fair Value of Financial Assets and Liabilities [Line Items]
Convertible debt	(2,665,690)	(2,500,477)
Foreign exchange derivative assets/liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Foreign exchange derivative assets	30,189	23,372
Foreign exchange derivative liabilities	(34,590)	(27,741)
Interest rate swap contract
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities		(19,872)
Level 1
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	5,803,427	5,765,317
Investment in joint venture	0
Level 1 | Cash
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,493,843	3,096,275
Level 1 | Cash equivalents
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	2,898,183	1,424,761
Level 1 | U.S. government and agency obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,324,919	1,179,280
Level 1 | U.S. corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 1 | High yield corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 1 | Asset-backed securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 1 | Municipal obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 1 | Commodity derivative liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities
Level 1 | Auction rate securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 1 | Foreign debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 1 | Publicly traded equity securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	86,482	65,001
Level 1 | Strategic investments held at cost
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 1 | Convertible debt
Fair Value of Financial Assets and Liabilities [Line Items]
Convertible debt
Level 1 | Foreign exchange derivative assets/liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Foreign exchange derivative assets
Foreign exchange derivative liabilities
Level 1 | Interest rate swap contract
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities
Level 2
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	5,522,215	5,003,216
Investment in joint venture	0
Level 2 | Cash
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 2 | Cash equivalents
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	362,034	10,000
Level 2 | U.S. government and agency obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	871,290	1,305,681
Level 2 | U.S. corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,480,450	1,407,753
Level 2 | High yield corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	510,412	447,479
Level 2 | Asset-backed securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	2,117	29,148
Level 2 | Municipal obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,022,889	816,081
Level 2 | Commodity derivative liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities	(588)	(3,093)
Level 2 | Auction rate securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 2 | Foreign debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	1,273,023	987,074
Level 2 | Publicly traded equity securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 2 | Strategic investments held at cost
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 2 | Convertible debt
Fair Value of Financial Assets and Liabilities [Line Items]
Convertible debt	(2,665,690)	(2,500,477)
Level 2 | Foreign exchange derivative assets/liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Foreign exchange derivative assets	30,189	23,372
Foreign exchange derivative liabilities	(34,590)	(27,741)
Level 2 | Interest rate swap contract
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities		(19,872)
Level 3
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	70,086	74,596
Investment in joint venture	32,745
Level 3 | Cash
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | Cash equivalents
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | U.S. government and agency obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | U.S. corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | High yield corporate debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | Asset-backed securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | Municipal obligations
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | Commodity derivative liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities
Level 3 | Auction rate securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	70,086	74,596
Level 3 | Foreign debt securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | Publicly traded equity securities
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments
Level 3 | Strategic investments held at cost
Fair Value of Financial Assets and Liabilities [Line Items]
Total cash and investments	351,855
Level 3 | Convertible debt
Fair Value of Financial Assets and Liabilities [Line Items]
Convertible debt
Level 3 | Foreign exchange derivative assets/liabilities
Fair Value of Financial Assets and Liabilities [Line Items]
Foreign exchange derivative assets
Foreign exchange derivative liabilities
Level 3 | Interest rate swap contract
Fair Value of Financial Assets and Liabilities [Line Items]
Commodity derivative liabilities