Represents the transfers into or out of level 1 fair value hierarchy that have taken place during the period.

No definition available.

Name:	seb_FairValueMeasurementTransfersIntoOrOutOfLevel1
Namespace Prefix:	seb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the transfers into or out of level 2 fair value hierarchy that have taken place during the period.

+ References

No definition available.

+ Details

Name:	seb_FairValueMeasurementTransfersIntoOrOutOfLevel2
Namespace Prefix:	seb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the transfers into or out of level 3 fair value hierarchy that have taken place during the period.

+ References

No definition available.

+ Details

Name:	seb_FairValueMeasurementTransfersIntoOrOutOfLevel3
Namespace Prefix:	seb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

+ Details

Name:	us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

+ Details

Name:	us-gaap_DerivativeAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or 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 liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13433-108611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313

+ Details

Name:	us-gaap_DerivativeLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740

+ Details

Name:	us-gaap_EquitySecuritiesFvNi
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial 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.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of financial and nonfinancial obligations.

+ References

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8,17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_MarginDepositAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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

+ Details

Name:	us-gaap_TradingSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_CommodityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=seb_DomesticEquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=seb_ForeignEquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=us-gaap_DomesticCorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=us-gaap_CollateralizedLoanObligationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=seb_HighYieldTradingDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=seb_MoneyMarketFundsHeldInTradingAccountsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=seb_OtherTradingInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_ForeignExchangeContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_OtherCurrentAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_ShortTermInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=us-gaap_FixedIncomeFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentAxis=us-gaap_OtherAggregatedInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivatives and Fair Value of Financial Instruments-Deferred Comp Securities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jan. 05, 2018	Dec. 31, 2017
Assets and liabilities measured at fair value on a recurring basis and also its level within the fair value hierarchy
Transfers that occurred into or out of level 1	$ 0
Transfers that occurred into or out of level 2	0
Transfers that occurred into or out of level 3	0
Assets:
Trading securities	1,264		$ 1,576
Liabilities:
Contingent consideration		$ 14
Commodities
Assets:
Margin account	36		20
Domestic equity securities
Assets:
Fair Value Equity	772		752
Foreign equity securities
Assets:
Fair Value Equity	302		319
Domestic debt securities held in mutual funds/ETFs/U.S. Treasuries
Assets:
Trading securities	122		439
Collateralized loan obligation
Assets:
Trading securities	30		29
High yield securities
Assets:
Trading securities	21		21
Money market funds held in trading accounts
Assets:
Trading securities	10		10
Other trading securities
Assets:
Trading securities	7		6
Recurring basis \| Fair Value
Assets:
Total Assets	1,315		1,629
Liabilities:
Contingent consideration	14
Liabilities	32		12
Recurring basis \| Fair Value \| Commodities
Assets:
Derivatives	2		4
Margin account	36		20
Liabilities:
Derivatives	17		6
Recurring basis \| Fair Value \| Foreign currencies
Assets:
Derivatives	2		3
Liabilities:
Derivatives	1		6
Recurring basis \| Fair Value \| Other current assets \| Commodities
Assets:
Derivative assets and liabilities, net basis	21		18
Recurring basis \| Fair Value \| Domestic equity securities \| Short term investments
Assets:
Trading securities	772		752
Recurring basis \| Fair Value \| Domestic equity securities \| Other current assets
Assets:
Trading securities	35		35
Recurring basis \| Fair Value \| Foreign equity securities \| Short term investments
Assets:
Trading securities	302		319
Recurring basis \| Fair Value \| Foreign equity securities \| Other current assets
Assets:
Trading securities	3		4
Recurring basis \| Fair Value \| Domestic debt securities held in mutual funds/ETFs/U.S. Treasuries \| Short term investments
Assets:
Trading securities	122		439
Recurring basis \| Fair Value \| Collateralized loan obligation \| Short term investments
Assets:
Trading securities	30		29
Recurring basis \| Fair Value \| High yield securities \| Short term investments
Assets:
Trading securities	21		21
Recurring basis \| Fair Value \| Money market funds held in trading accounts \| Short term investments
Assets:
Trading securities	10		10
Recurring basis \| Fair Value \| Money market funds held in trading accounts \| Other current assets
Assets:
Trading securities	6		5
Recurring basis \| Fair Value \| Other trading securities \| Short term investments
Assets:
Trading securities	7		6
Recurring basis \| Fair Value \| Fixed income securities \| Other current assets
Assets:
Trading securities	2		2
Recurring basis \| Fair Value \| Other \| Other current assets
Assets:
Trading securities	1
Recurring basis \| Level 1
Assets:
Total Assets	1,270		1,596
Liabilities:
Liabilities	17		6
Recurring basis \| Level 1 \| Commodities
Assets:
Derivatives	2		4
Liabilities:
Derivatives	17		6
Recurring basis \| Level 1 \| Domestic equity securities \| Short term investments
Assets:
Trading securities	772		752
Recurring basis \| Level 1 \| Domestic equity securities \| Other current assets
Assets:
Trading securities	35		35
Recurring basis \| Level 1 \| Foreign equity securities \| Short term investments
Assets:
Trading securities	302		319
Recurring basis \| Level 1 \| Foreign equity securities \| Other current assets
Assets:
Trading securities	3		4
Recurring basis \| Level 1 \| Domestic debt securities held in mutual funds/ETFs/U.S. Treasuries \| Short term investments
Assets:
Trading securities	112		438
Recurring basis \| Level 1 \| High yield securities \| Short term investments
Assets:
Trading securities	21		21
Recurring basis \| Level 1 \| Money market funds held in trading accounts \| Short term investments
Assets:
Trading securities	10		10
Recurring basis \| Level 1 \| Money market funds held in trading accounts \| Other current assets
Assets:
Trading securities	6		5
Recurring basis \| Level 1 \| Other trading securities \| Short term investments
Assets:
Trading securities	5		6
Recurring basis \| Level 1 \| Fixed income securities \| Other current assets
Assets:
Trading securities	2		2
Recurring basis \| Level 2
Assets:
Total Assets	45		33
Liabilities:
Liabilities	1		6
Recurring basis \| Level 2 \| Foreign currencies
Assets:
Derivatives	2		3
Liabilities:
Derivatives	1		6
Recurring basis \| Level 2 \| Domestic debt securities held in mutual funds/ETFs/U.S. Treasuries \| Short term investments
Assets:
Trading securities	10		1
Recurring basis \| Level 2 \| Collateralized loan obligation \| Short term investments
Assets:
Trading securities	30		$ 29
Recurring basis \| Level 2 \| Other trading securities \| Short term investments
Assets:
Trading securities	2
Recurring basis \| Level 2 \| Other \| Other current assets
Assets:
Trading securities	1
Recurring basis \| Level 3
Liabilities:
Contingent consideration	14
Liabilities	$ 14