Derivative Financial Instruments (Fair Value And Related Number Of Derivative Contracts Categorized By Predominant Risk Exposure) (Details) $ in Thousands	Dec. 31, 2015 USD ($) contract	Dec. 31, 2014 USD ($) contract
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 4,428,245	$ 5,165,613
Fair Value, Liabilities	4,476,241	5,220,133
Counterparty/cash-collateral netting, Assets	(4,165,446)	(4,759,345)
Counterparty/cash-collateral netting, Liabilities	(4,257,998)	(4,856,618)
Total assets	262,799	406,268
Total liabilities	218,243	363,515
Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 2,910,093	$ 2,299,807
Number of Contracts, Assets \| contract	56,748	71,505
Fair Value, Liabilities	$ 2,849,958	$ 2,292,691
Number of Contracts, Liabilities \| contract	74,904	89,861
Foreign Exchange Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 472,869	$ 1,514,881
Number of Contracts, Assets \| contract	8,118	12,861
Fair Value, Liabilities	$ 470,649	$ 1,519,349
Number of Contracts, Liabilities \| contract	7,404	12,752
Equity Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 1,017,611	$ 1,050,990
Number of Contracts, Assets \| contract	3,057,754	2,271,507
Fair Value, Liabilities	$ 1,094,597	$ 1,058,015
Number of Contracts, Liabilities \| contract	2,947,416	2,051,469
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 8,248	$ 276,726
Number of Contracts, Assets \| contract	2,867	1,031,568
Fair Value, Liabilities	$ 882	$ 303,206
Number of Contracts, Liabilities \| contract	1,973	1,020,418
Credit Contracts: Centrally Cleared Swaps [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 2,447	$ 17,831
Number of Contracts, Assets \| contract	299	27
Fair Value, Liabilities	$ 841	$ 23,264
Number of Contracts, Liabilities \| contract	44	22
Credit Contracts: Other Credit Derivatives [Member]
Derivatives, Fair Value [Line Items]
Fair Value, Assets	$ 16,977	$ 5,378
Number of Contracts, Assets \| contract	100	18
Fair Value, Liabilities	$ 59,314	$ 23,608
Number of Contracts, Liabilities \| contract	135	27

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 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579245-113959

Reference 2: 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

+ 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 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

Reference 2: 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 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

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_DerivativeLiabilityNumberOfInstrumentsHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
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_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

+ 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

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
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_DerivativeInstrumentRiskAxis=us-gaap_EquityContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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