Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Apr. 02, 2011
Assets
Total assets measured at fair value	$ 2,864,667	$ 2,608,477
Liabilities
Foreign currency forward contracts, net	7,058
Fair Value Liabilities, Convertible debentures - embedded derivative	1,352	945
Total liabilities measured at fair value	8,410	945
Net assets measured at fair value	2,856,257	2,607,532
Fair Value, Inputs, Level 1 [Member]
Assets
Total assets measured at fair value	512,723	327,939
Liabilities
Foreign currency forward contracts, net	0
Fair Value Liabilities, Convertible debentures - embedded derivative	0	0
Total liabilities measured at fair value	0	0
Net assets measured at fair value	512,723	327,939
Fair Value, Inputs, Level 2 [Member]
Assets
Total assets measured at fair value	2,323,943	2,245,588
Liabilities
Foreign currency forward contracts, net	7,058
Fair Value Liabilities, Convertible debentures - embedded derivative	0	0
Total liabilities measured at fair value	7,058	0
Net assets measured at fair value	2,316,885	2,245,588
Fair Value, Inputs, Level 3 [Member]
Assets
Total assets measured at fair value	28,001	34,950
Liabilities
Foreign currency forward contracts, net	0
Fair Value Liabilities, Convertible debentures - embedded derivative	1,352	945
Total liabilities measured at fair value	1,352	945
Net assets measured at fair value	26,649	34,005
Cash And Cash Equivalents [Member] | Money Market Funds [Member]
Assets
Total assets measured at fair value	324,574	275,596
Cash And Cash Equivalents [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	29,994	79,984
Cash And Cash Equivalents [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	109,992	485,315
Cash And Cash Equivalents [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value		129,972
Cash And Cash Equivalents [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	109,989	161,970
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets
Total assets measured at fair value	324,574	275,596
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value		29,998
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Assets
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	29,994	79,984
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	109,992	485,315
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value		99,974
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	109,989	161,970
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Assets
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value		0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	109,982	10,000
Short-Term Investments [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	389,882	224,896
Short-Term Investments [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	10,006
Short-Term Investments [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value		45
Short-Term Investments [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	311,972	22,400
Short-Term Investments [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	277,429	384,428
Short-Term Investments [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		62,261
Short-Term Investments [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	35	24
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value		0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	146,265	14,404
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	109,982	10,000
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	389,882	224,896
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	10,006
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value		45
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	165,707	7,996
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	277,429	384,428
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		62,261
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	35	24
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Bank Certificates of Deposit [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Paper [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value		0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government and Agency Securities [Member]
Assets
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	162,625	25,566
Long-Term Investments [Member] | Auction Rate Securities [Member]
Assets
Total assets measured at fair value	28,001	34,950
Long-Term Investments [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value	27,993	16,913
Long-Term Investments [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	70,597	53,511
Long-Term Investments [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		29,869
Long-Term Investments [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	882,237	605,643
Long-Term Investments [Member] | Debt Mutual Fund [Member]
Assets
Total assets measured at fair value	19,359
Long-Term Investments [Member] | Foreign Currency Forward Contracts, Net [Member]
Assets
Total assets measured at fair value		5,134
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Auction Rate Securities [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	22,525	7,941
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Mutual Fund [Member]
Assets
Total assets measured at fair value	19,359
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Currency Forward Contracts, Net [Member]
Assets
Total assets measured at fair value		0
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	162,625	25,566
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Auction Rate Securities [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value	27,993	16,913
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	48,072	45,570
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		29,869
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	882,237	605,643
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Mutual Fund [Member]
Assets
Total assets measured at fair value	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Currency Forward Contracts, Net [Member]
Assets
Total assets measured at fair value		5,134
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Auction Rate Securities [Member]
Assets
Total assets measured at fair value	28,001	34,950
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government and Agency Securities [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Floating Rate Notes [Member]
Assets
Total assets measured at fair value		0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-Backed Securities [Member]
Assets
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Mutual Fund [Member]
Assets
Total assets measured at fair value	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Currency Forward Contracts, Net [Member]
Assets
Total assets measured at fair value		$ 0