Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Mar. 28, 2015	Mar. 29, 2014
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Derivative Asset		$ 1,713
Fair Value, Inputs, Level 1 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Derivative Asset		0
Fair Value, Inputs, Level 2 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Derivative Asset		1,713
Fair Value, Inputs, Level 3 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Derivative Asset		0
Fair Value, Measurements, Recurring [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	3,471,356	3,607,062
Derivative Liability	9,251
Total liabilities measured at fair value	9,251
Net assets measured at fair value	3,462,105
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	492,097	637,959
Derivative Liability	0
Total liabilities measured at fair value	0
Net assets measured at fair value	492,097
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	2,968,947	2,948,943
Derivative Liability	9,251
Total liabilities measured at fair value	9,251
Net assets measured at fair value	2,959,696
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	10,312	20,160
Derivative Liability	0
Total liabilities measured at fair value	0
Net assets measured at fair value	10,312
Fair Value, Measurements, Recurring [Member] | 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	235,583	213,988
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	229,999	131,990
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	89,995	319,970
Fair Value, Measurements, Recurring [Member] | 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	200,392	69,998
Fair Value, Measurements, Recurring [Member] | 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	37,996	194,984
Fair Value, Measurements, Recurring [Member] | 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	235,583	213,988
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | 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	0	69,998
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	229,999	131,990
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	89,995	319,970
Fair Value, Measurements, Recurring [Member] | 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	200,392	0
Fair Value, Measurements, Recurring [Member] | 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	37,996	194,984
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	75,000	234,916
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	339,029	226,828
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	40,006	15,780
Fair Value, Measurements, Recurring [Member] | 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	557,524	438,445
Fair Value, Measurements, Recurring [Member] | 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	159,936	159,951
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	204,510
Fair Value, Measurements, Recurring [Member] | 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	897,776	387,508
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Debt Mutual Fund [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	38,608	20,216
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Bank Loans [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	98,100
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | 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	0
Fair Value, Measurements, Recurring [Member] | 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	256,514	349,023
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Short-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
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Bank Loans [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	75,000	234,916
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	339,029	226,828
Fair Value, Measurements, Recurring [Member] | 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	40,006	15,780
Fair Value, Measurements, Recurring [Member] | 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	301,010	89,422
Fair Value, Measurements, Recurring [Member] | 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	159,936	159,951
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	204,510
Fair Value, Measurements, Recurring [Member] | 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	897,776	387,508
Fair Value, Measurements, Recurring [Member] | Short-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	38,608	20,216
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Bank Loans [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	98,100
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0	0
Fair Value, Measurements, Recurring [Member] | 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	0
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Short-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
Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Bank Loans [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value		209,274
Fair Value, Measurements, Recurring [Member] | 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	10,312	20,160
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Municipal Bonds [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	9,650	15,986
Fair Value, Measurements, Recurring [Member] | 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		41,076
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	7,948
Fair Value, Measurements, Recurring [Member] | 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	182,400	847,581
Fair Value, Measurements, Recurring [Member] | 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	56,592	56,698
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value		0
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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		4,950
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value		209,274
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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	9,650	15,986
Fair Value, Measurements, Recurring [Member] | 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		36,126
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	7,948
Fair Value, Measurements, Recurring [Member] | 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	182,400	847,581
Fair Value, Measurements, Recurring [Member] | 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	56,592	56,698
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Non-financial institution securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value		0
Fair Value, Measurements, Recurring [Member] | 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	10,312	20,160
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Assets and Liabilities Measured at Fair Value on a Recurring Basis
Total assets measured at fair value	0
Fair Value, Measurements, Recurring [Member] | 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
Fair Value, Measurements, Recurring [Member] | 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