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

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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66011266&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://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_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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.1(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

- Definition

Amount of unrealized holding gain (loss) recognized in the income statement for 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 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(c))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e24584-111560

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

+ Details

Name:	us-gaap_TradingSecuritiesUnrealizedHoldingGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_IndustrialMember
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:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=iep_HertzMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=iep_HerbalifeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments and Related Matters Investment Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule of Investments [Line Items]
Investments	$ 8,364		$ 10,369
Securities sold, not yet purchased, at fair value	299		1,023
Investment Segment
Schedule of Investments [Line Items]
Investments	7,518		9,532
Securities sold, not yet purchased, at fair value	299		1,023
Portion of trading gains (loss) that relates to trading securities still held at balance sheet date	175	$ 444
Investment Segment \| Equity securities:
Schedule of Investments [Line Items]
Investments	7,360		9,377
Securities sold, not yet purchased, at fair value	281		988
Investment Segment \| Corporate debt securities
Schedule of Investments [Line Items]
Investments	158		155
Investment Segment \| Basic materials \| Equity securities:
Schedule of Investments [Line Items]
Investments	705		1,170
Investment Segment \| Consumer, non-cyclical \| Equity securities:
Schedule of Investments [Line Items]
Investments	2,628		2,551
Securities sold, not yet purchased, at fair value	86		101
Investment Segment \| Consumer, cyclical \| Equity securities:
Schedule of Investments [Line Items]
Investments	1,261		777
Securities sold, not yet purchased, at fair value	127		667
Investment Segment \| Consumer, cyclical \| Corporate debt securities
Schedule of Investments [Line Items]
Securities sold, not yet purchased, at fair value	18		35
Investment Segment \| Energy \| Equity securities:
Schedule of Investments [Line Items]
Investments	1,453		1,489
Securities sold, not yet purchased, at fair value	0		110
Investment Segment \| Financial \| Equity securities:
Schedule of Investments [Line Items]
Investments	149		2,185
Investment Segment \| Industrial \| Equity securities:
Schedule of Investments [Line Items]
Securities sold, not yet purchased, at fair value	68		110
Investment Segment \| Technology \| Equity securities:
Schedule of Investments [Line Items]
Investments	956		833
Investment Segment \| Other \| Equity securities:
Schedule of Investments [Line Items]
Investments	$ 208		372
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	28.00%
Unrealized gain (loss) on equity method investments under fair value option	$ (52)	(94)
Fair value of equity method investment under fair value option	$ 465		517
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	20.90%
Unrealized gain (loss) on equity method investments under fair value option	$ 544	$ 182
Fair value of equity method investment under fair value option	$ 1,800		$ 1,200