Derivative Financial Instruments (Fair Value And Related Number Of Derivative Contracts Categorized By Predominant Risk Exposure) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 2,901,691	$ 2,514,683
Fair Value, Liabilities	2,973,365	2,532,690
Counterparty/cash-collateral netting, Assets	(2,648,507)	(2,253,589)
Counterparty/cash-collateral netting, Liabilities	(2,747,077)	(2,352,611)
Total Derivative Assets per Consolidated Statement of Financial Condition	253,184	261,094
Total Derivative Liabilities per Consolidated Statement of Financial Condition	226,288	180,079
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	1,672,195	1,165,977
Number of Contracts, Assets	48,853	63,967
Fair Value, Liabilities	1,678,742	1,131,166
Number of Contracts, Liabilities	67,733	77,338
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	474,633	653,772
Number of Contracts, Assets	64,945	118,707
Fair Value, Liabilities	488,763	693,658
Number of Contracts, Liabilities	62,943	112,417
Equity Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	553,622	501,784
Number of Contracts, Assets	1,820,612	1,742,343
Fair Value, Liabilities	555,213	474,985
Number of Contracts, Liabilities	1,751,789	1,800,603
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	196,560	141,280
Number of Contracts, Assets	848,890	797,529
Fair Value, Liabilities	221,075	173,119
Number of Contracts, Liabilities	841,714	788,717
Credit Contracts: Centrally Cleared Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	3,386	49,531
Number of Contracts, Assets	4	49
Fair Value, Liabilities	6,550	51,632
Number of Contracts, Liabilities	9	46
Credit Contracts: Other Credit Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	1,295	2,339
Number of Contracts, Assets	15	16
Fair Value, Liabilities	$ 23,022	$ 8,130
Number of Contracts, Liabilities	31	19

Derivative, Fair Value of Derivative Asset, Amount Netting in Consolidated Statement of Financial Condition

No definition available.

Name:	luk_DerivativeFairValueOfDerivativeAssetAmountNettingInConsolidatedStatementOfFinancialCondition
Namespace Prefix:	luk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Derivative, Fair Value of Derivative Liability, Amount Netting in Consolidated Statement of Financial Condition

+ References

No definition available.

+ Details

Name:	luk_DerivativeFairValueOfDerivativeLiabilityAmountNettingInConsolidatedStatementOfFinancialCondition
Namespace Prefix:	luk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The number of derivative instruments of a particular derivative asset or group of derivative assets held by the entity.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5580258-113959

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeAssetNumberOfInstrumentsHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value, before 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 elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226000-175313

+ Details

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

- Definition

Fair value, before 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 elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

+ Details

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

- Definition

The number of derivative instruments of a particular derivative liability or group of derivative liabilities held by the entity.

+ References

+ Details

Name:	us-gaap_DerivativeLiabilityNumberOfInstrumentsHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

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

- Definition

The fair value as of the balance sheet date of firm holdings in all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments. Their value is derived from the values of one or more underlying assets, reference rates, or indices of asset values. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph c

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

+ Details

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

- Definition

Fair value of obligations arising from derivatives and other contracts sold short.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 940

-SubTopic 320

-Section 35

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35711043&loc=d3e42429-110968

+ Details

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