Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Mar. 30, 2013	Mar. 31, 2012
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	$ 3,289,221	$ 3,063,038
Derivative financial instruments, net	1,615	3,070
Fair Value Liabilities, Convertible debentures - embedded derivative	1,090	931
Total liabilities measured at fair value	2,705	4,001
Net assets measured at fair value	3,286,516	3,059,037
Fair Value, Inputs, Level 1 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	675,379	647,355
Derivative financial instruments, net	0	0
Fair Value Liabilities, Convertible debentures - embedded derivative	0	0
Total liabilities measured at fair value	0	0
Net assets measured at fair value	675,379	647,355
Fair Value, Inputs, Level 2 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	2,585,142	2,386,754
Derivative financial instruments, net	1,615	3,070
Fair Value Liabilities, Convertible debentures - embedded derivative	0	0
Total liabilities measured at fair value	1,615	3,070
Net assets measured at fair value	2,583,527	2,383,684
Fair Value, Inputs, Level 3 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	28,700	28,929
Derivative financial instruments, net	0	0
Fair Value Liabilities, Convertible debentures - embedded derivative	1,090	931
Total liabilities measured at fair value	1,090	931
Net assets measured at fair value	27,610	27,998
Cash And Cash Equivalents [Member] | Money Market Funds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	108,311	232,017
Cash And Cash Equivalents [Member] | Bank Certificates of Deposit [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	79,995	29,994
Cash And Cash Equivalents [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	208,667	233,980
Cash And Cash Equivalents [Member] | U.S. Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	95,039	160,021
Cash And Cash Equivalents [Member] | Foreign Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	54,989	68,993
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	108,311	232,017
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Bank Certificates of Deposit [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	95,039	75,036
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	79,995	29,994
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	208,667	233,980
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	84,985
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	54,989	68,993
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Bank Certificates of Deposit [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	44,992	129,978
Short-Term Investments [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	294,883	360,887
Short-Term Investments [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	40,728	14,257
Short-Term Investments [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	3,706
Short-Term Investments [Member] | U.S. Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	491,898	442,694
Short-Term Investments [Member] | Foreign Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	214,912	180,958
Short-Term Investments [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	68	31
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Bank Certificates of Deposit [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	416,887	322,763
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Bank Certificates of Deposit [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	44,992	129,978
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	294,883	360,887
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	40,728	14,257
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	3,706
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	75,011	119,931
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	214,912	180,958
Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	68	31
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Bank Certificates of Deposit [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial Paper [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	235,275	175,415
Long-Term Investments [Member] | Student loan auction rate securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	28,700	28,929
Long-Term Investments [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	21,234	26,160
Long-Term Investments [Member] | U.S. Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	110,285	66,198
Long-Term Investments [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	1,192,612	892,745
Long-Term Investments [Member] | Debt Mutual Fund [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	62,927	19,781
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Student loan auction rate securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	55,142	17,539
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Mutual Fund [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	235,275	175,415
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Student loan auction rate securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	21,234	26,160
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	55,143	48,659
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	1,192,612	892,745
Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Mutual Fund [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	62,927	19,781
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Student loan auction rate securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	28,700	28,929
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
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 and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-Backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Mutual Fund [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	$ 0	$ 0