Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Accounting policies [Line Items]
Assets		$ 22,824		$ 22,824		$ 24,639
Total liabilities		13,951		13,951		13,697
Debt		8,146		8,146		8,192
Fair value of long-term debt		8,100		8,100		7,600
Cash held at consolidated affiliated partnerships and restricted cash		2,687		2,687		1,151
Operating lease right-of-use asset		576		576		624
Operating lease liability		594		594		647
Cash held at consolidated affiliated partnerships
Accounting policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash		2,365		2,365		86
Restricted cash
Accounting policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash		322		322		1,065
Energy Segment
Accounting policies [Line Items]
Assets		4,637		4,637		4,673
Total liabilities		2,699		2,699		2,375
Debt		1,690		1,690		1,195
Cash held at consolidated affiliated partnerships and restricted cash		7		7		0
Deferred revenue		12		12		28
Recorded revenue				27	$ 68
Revenue, remaining performance obligation		7		7
Revenue, current portion of remaining performance obligation		1		1
Operating lease right-of-use asset		42		42		48
Operating lease liability		41		41		48
Automotive Segment
Accounting policies [Line Items]
Assets		3,160		3,160		3,495
Total liabilities		1,506		1,506		1,745
Debt		333		333		405
Cash held at consolidated affiliated partnerships and restricted cash		0		0		0
Deferred revenue		41		41		42
Recorded revenue		6	$ 5	19	$ 17
Operating lease right-of-use asset		454		454		501
Operating lease liability		476		476		527
Real Estate Segment
Accounting policies [Line Items]
Assets		490		490		514
Total liabilities		56		56		40
Debt		2		2		2
Cash held at consolidated affiliated partnerships and restricted cash		9		9		2
Food Packaging Segment
Accounting policies [Line Items]
Assets		506		506		517
Total liabilities		448		448		464
Debt		258		258		268
Cash held at consolidated affiliated partnerships and restricted cash		1		1		1
Operating lease right-of-use asset		32		32		34
Operating lease liability		36		36		38
Icahn Enterprises Holdings
Accounting policies [Line Items]
Assets		22,824		22,824		24,639
Total liabilities		13,954		13,954		13,700
Debt		8,149		8,149		8,195
Cash held at consolidated affiliated partnerships and restricted cash		2,687		2,687		1,151
Cash and cash equivalents | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		49		49		42
Cash held at consolidated affiliated partnerships and restricted cash | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		2,650		2,650		989
Investments [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		6,177		6,177		9,207
Due from brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		1,682		1,682		858
Accounts receivable, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		20		20		35
Inventories, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		46		46		48
Property, plant and equipment, net [Member]
Accounting policies [Line Items]
Financing lease right-of-use asset		68		68		77
Property, plant and equipment, net [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		1,062		1,062		1,123
Unrealized gain on derivative contracts | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		1,433		1,433		182
Intangible assets, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		237		237		251
Other assets [Member]
Accounting policies [Line Items]
Operating lease right-of-use asset		576		576		624
Other assets [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets		31		31		49
Accounts Payable [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities		25		25		25
Accrued expenses and other liabilities
Accounting policies [Line Items]
Operating lease liability		594		594		647
Accrued expenses and other liabilities | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities		71		71		98
Unrealized loss on derivative contracts | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities		172		172		1,215
Securities sold, not yet purchased, at fair value | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities		970		970		1,190
Due to brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities		1,971		1,971		54
Debt
Accounting policies [Line Items]
Financing lease liability		83		83		93
Debt | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities		$ 634		$ 634		$ 633
Icahn Enterprises Holdings
Accounting policies [Line Items]
Percentage of equity ownership in operating subsidiary	89.00%			99.00%
Viskase
Accounting policies [Line Items]
Percentage of equity ownership in operating subsidiary				78.60%
Viskase | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Percentage of equity ownership in operating subsidiary				50.00%