Investments and Fair Value Measurements-Fin Assets and Liabilities 1 (Details 2) (USD $)	Mar. 29, 2015	Dec. 28, 2014
Financial Liabilities measured at fair value on a recurring basis
Derivative liabilities	$ 1,448,000us-gaap_DerivativeLiabilities	$ 8,224,000us-gaap_DerivativeLiabilities
Significant Unobservable Inputs (Level 3) [Member]
Financial assets measured at fair value on a recurring basis
Total financial assets	0	0
Financial Liabilities measured at fair value on a recurring basis
Total financial liabilities	0	0
Fair Value, Measurements, Recurring [Member]
Financial assets measured at fair value on a recurring basis
Total financial assets	4,208,620,000	4,776,694,000
Financial Liabilities measured at fair value on a recurring basis
Total financial liabilities	1,448,000	8,224,000
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets measured at fair value on a recurring basis
Total financial assets	439,248,000	558,295,000
Financial Liabilities measured at fair value on a recurring basis
Total financial liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Financial assets measured at fair value on a recurring basis
Total financial assets	3,769,372,000	4,218,399,000
Financial Liabilities measured at fair value on a recurring basis
Total financial liabilities	1,448,000	8,224,000
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Financial assets measured at fair value on a recurring basis
Total financial assets	0	0
Financial Liabilities measured at fair value on a recurring basis
Total financial liabilities	0	0
Derivative Liabilities [Member] \| Fair Value, Measurements, Recurring [Member]
Financial Liabilities measured at fair value on a recurring basis
Derivative liabilities	1,448,000	8,224,000
Derivative Liabilities [Member] \| Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial Liabilities measured at fair value on a recurring basis
Derivative liabilities	0	0
Derivative Liabilities [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Financial Liabilities measured at fair value on a recurring basis
Derivative liabilities	1,448,000	8,224,000
Derivative Liabilities [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Financial Liabilities measured at fair value on a recurring basis
Derivative liabilities	0	0
Money Market Funds [Member] \| Fair Value, Measurements, Recurring [Member]
Financial assets measured at fair value on a recurring basis
Money market funds	432,433,000	533,133,000
Money Market Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets measured at fair value on a recurring basis
Money market funds	432,433,000	533,133,000
Money Market Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Financial assets measured at fair value on a recurring basis
Money market funds	0	0
Money Market Funds [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Financial assets measured at fair value on a recurring basis
Money market funds	0	0
Fixed Income Securities [Member] \| Fair Value, Measurements, Recurring [Member]
Financial assets measured at fair value on a recurring basis
Fixed income securities	3,772,944,000	4,238,761,000
Fixed Income Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets measured at fair value on a recurring basis
Fixed income securities	6,815,000	25,162,000
Fixed Income Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Financial assets measured at fair value on a recurring basis
Fixed income securities	3,766,129,000	4,213,599,000
Fixed Income Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Financial assets measured at fair value on a recurring basis
Fixed income securities	0	0
Derivative Assets [Member] \| Fair Value, Measurements, Recurring [Member]
Financial assets measured at fair value on a recurring basis
Derivative assets	3,243,000	4,800,000
Derivative Assets [Member] \| Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets measured at fair value on a recurring basis
Derivative assets	0	0
Derivative Assets [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Financial assets measured at fair value on a recurring basis
Derivative assets	3,243,000	4,800,000
Derivative Assets [Member] \| Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Financial assets measured at fair value on a recurring basis
Derivative assets	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

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-Name Accounting Standards Codification

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-Name Accounting Standards Codification

-Topic 825

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

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-Name Accounting Standards Codification

-Topic 815

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-Section 45

-Paragraph 6

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Available-for-Sale Securities

-URI http://asc.fasb.org/extlink&oid=6505594

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Glossary Trading Securities

-URI http://asc.fasb.org/extlink&oid=6526789

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph a, f, g

-Article 7

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-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 35

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Fair value of financial and nonfinancial obligations.

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