Fair Value of Equity Method Investment Under Fair Value Option

No definition available.

Name:	iep_FairValueOfEquityMethodInvestmentUnderFairValueOption
Namespace Prefix:	iep_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Unrealized gain (loss) on equity method investments under fair value option

+ References

No definition available.

+ Details

Name:	iep_Unrealizedgainonequitymethodinvestmentsunderfairvalueoption
Namespace Prefix:	iep_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of unrealized gain (loss) on investment in debt and equity securities.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtAndEquitySecuritiesUnrealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value of obligations incurred from short sales.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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_FinancialInstrumentsSoldNotYetPurchasedAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sum of the carrying amounts as of the balance sheet date of all investments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(h))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=iep_InvestmentSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	invest_InvestmentSectorAxis=iep_BasicMaterialsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSectorAxis=iep_ConsumerNonCyclicalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSectorAxis=iep_ConsumerCyclicalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSectorAxis=iep_EnergySectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSectorAxis=iep_FinancialMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSectorAxis=iep_TechnologyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentSectorAxis=iep_OtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=iep_HertzMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=iep_HerbalifeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=iep_CaesarsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments and Related Matters Investment Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Schedule of Investments [Line Items]
Investments	$ 8,103		$ 8,337
Securities sold, not yet purchased, at fair value	447		468
Investment Segment
Schedule of Investments [Line Items]
Investments	7,130		6,867
Securities sold, not yet purchased, at fair value	447		468
Unrealized gain on debt and equity securities still held	558	$ 175
Investment Segment \| Equity securities:
Schedule of Investments [Line Items]
Investments	6,945		6,686
Securities sold, not yet purchased, at fair value	447		468
Investment Segment \| Corporate debt securities
Schedule of Investments [Line Items]
Investments	185		181
Investment Segment \| Basic materials \| Equity securities:
Schedule of Investments [Line Items]
Investments	456		414
Investment Segment \| Consumer, non-cyclical \| Equity securities:
Schedule of Investments [Line Items]
Investments	2,005		2,161
Securities sold, not yet purchased, at fair value	42		57
Investment Segment \| Consumer, cyclical \| Equity securities:
Schedule of Investments [Line Items]
Investments	1,627		1,161
Securities sold, not yet purchased, at fair value	96		106
Investment Segment \| Consumer, cyclical \| Corporate debt securities
Schedule of Investments [Line Items]
Securities sold, not yet purchased, at fair value	0		0
Investment Segment \| Energy \| Equity securities:
Schedule of Investments [Line Items]
Investments	1,654		1,598
Securities sold, not yet purchased, at fair value	309		305
Investment Segment \| Financial \| Equity securities:
Schedule of Investments [Line Items]
Investments	209		167
Investment Segment \| Technology \| Equity securities:
Schedule of Investments [Line Items]
Investments	819		1,040
Investment Segment \| Other \| Equity securities:
Schedule of Investments [Line Items]
Investments	$ 175		145
Hertz \| Investment Segment
Schedule of Investments [Line Items]
Ownership percentage in investment measured at fair value that would otherwise be accounted for under equity method	23.10%
Unrealized gain (loss) on equity method investments under fair value option	$ 95	(52)
Fair value of equity method investment under fair value option	$ 337		320
Herbalife \| Investment Segment
Schedule of Investments [Line Items]
Ownership percentage in investment measured at fair value that would otherwise be accounted for under equity method	18.40%
Unrealized gain (loss) on equity method investments under fair value option	$ (168)	$ 544
Fair value of equity method investment under fair value option	$ 1,500		$ 1,700
Caesars \| Investment Segment
Schedule of Investments [Line Items]
Ownership percentage in investment measured at fair value that would otherwise be accounted for under equity method	11.70%
Unrealized gain (loss) on equity method investments under fair value option	$ 26
Fair value of equity method investment under fair value option	$ 690