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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- Definition

Amount of unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

+ References

No definition available.

+ Details

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- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

No definition available.

+ Details

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Namespace Prefix:	seb_
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- Definition

Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

+ 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1)(g))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: 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(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: 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(6))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: 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

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- Definition

Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82896770&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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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Investments (Details) - USD ($) $ in Millions	3 Months Ended
Investments (Details) - USD ($) $ in Millions	Mar. 31, 2018	Apr. 01, 2017	Dec. 31, 2017
Investments
Total trading short-term investments	$ 1,264		$ 1,576
Change in unrealized gains (losses) on trading securities	(22)	$ 38
Domestic equity securities
Investments
Fair Value Equity	744		752
Foreign equity securities
Investments
Fair Value Equity	320		319
Domestic debt securities held in mutual funds/ETFs/U.S. Treasuries
Investments
Fair Value	135		439
Collateralized loan obligation
Investments
Fair Value	28		29
High yield securities
Investments
Fair Value	21		21
Money market funds held in trading accounts
Investments
Fair Value	8		10
Other trading securities
Investments
Fair Value	8		6
Denominated in foreign currencies \| Money market funds \| Maximum
Investments
Fair Value	1		1
Denominated in foreign currencies \| Foreign equity securities
Investments
Fair Value Equity	111		114
Denominated in Euros \| Foreign equity securities
Investments
Fair Value Equity	47		48
Denominated in Japanese Yen \| Foreign equity securities
Investments
Fair Value Equity	24		25
Denominated in British pounds \| Foreign equity securities
Investments
Fair Value Equity	19		20
Denominated in Swiss Franc \| Foreign equity securities
Investments
Fair Value Equity	6		6
Denominated in other foreign currencies \| Foreign equity securities
Investments
Fair Value Equity	$ 15		$ 15