Investments (Details) - USD ($) $ in Millions	Apr. 02, 2016	Dec. 31, 2015
Investments
Total short term investments, amortized cost	$ 1,190	$ 1,269
Total short term investments, fair value	1,185	1,254
Available-for-sale securities.
Investments
Amortized Cost	133	81
Fair Value	133	81
Money market funds
Investments
Amortized Cost	133	81
Fair Value	133	81
Trading securities.
Investments
Amortized Cost	1,057	1,188
Fair Value	1,052	1,173
Domestic equity securities
Investments
Amortized Cost	466	475
Fair Value	469	466
Domestic debt securities
Investments
Amortized Cost	351	452
Fair Value	351	450
Foreign equity securities
Investments
Amortized Cost	119	120
Fair Value	114	120
High yield trading debt securities
Investments
Amortized Cost	94	108
Fair Value	93	104
Money market funds held in trading accounts
Investments
Amortized Cost	17	22
Fair Value	17	22
Collateralized loan obligation
Investments
Amortized Cost	10	10
Fair Value	8	10
Other trading securities
Investments
Amortized Cost		1
Fair Value		1
Denominated in foreign currencies \| Money market funds
Investments
Fair Value	2	3
Denominated in foreign currencies \| Foreign equity securities
Investments
Fair Value	76	80
Denominated in Euros \| Foreign equity securities
Investments
Fair Value	25	25
Denominated in Japanese Yen \| Foreign equity securities
Investments
Fair Value	17	20
Denominated in British pounds \| Foreign equity securities
Investments
Fair Value	14	15
Denominated in Swiss Franc \| Foreign equity securities
Investments
Fair Value	6	7
Denominated in other foreign currencies \| Foreign equity securities
Investments
Fair Value	$ 14	$ 13

Line items represent reporting concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 12
-Sentence Column A

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Investments which are intended to be sold in the short term (usually less than one year or the normal operating cycle, whichever is longer) including trading securities, available-for-sale securities, held-to-maturity securities, and other short-term investments not otherwise listed in the existing taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26626-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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