Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Accounting policies [Line Items]
Assets	$ 24,706		$ 24,706		$ 24,639
Total liabilities	14,441		14,441		13,697
Debt	8,162		8,162		8,192
Fair value of long-term debt	7,900		7,900		7,600
Cash held at consolidated affiliated partnerships and restricted cash	916		916		1,151
Operating lease right-of-use asset	595		595		624
Operating lease liability	616		616		647
Cash held at consolidated affiliated partnerships
Accounting policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash	540		540		86
Restricted cash
Accounting policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash	376		376		1,065
Energy Segment
Accounting policies [Line Items]
Assets	4,705		4,705		4,673
Total liabilities	2,644		2,644		2,375
Debt	1,690		1,690		1,195
Cash held at consolidated affiliated partnerships and restricted cash	0		0		0
Deferred revenue	3		3		28
Recorded revenue	21	$ 56	27	$ 68
Revenue, remaining performance obligation	8		8
Revenue, current portion of remaining performance obligation	1		1
Operating lease right-of-use asset	42		42		48
Operating lease liability	42		42		48
Automotive Segment
Accounting policies [Line Items]
Assets	3,284		3,284		3,495
Total liabilities	1,547		1,547		1,745
Debt	366		366		405
Cash held at consolidated affiliated partnerships and restricted cash	0		0		0
Deferred revenue	40		40		42
Recorded revenue	7	$ 6	13	$ 12
Operating lease right-of-use asset	474		474		501
Operating lease liability	498		498		527
Real Estate Segment
Accounting policies [Line Items]
Assets	517		517		514
Total liabilities	59		59		40
Debt	2		2		2
Cash held at consolidated affiliated partnerships and restricted cash	4		4		2
Food Packaging Segment
Accounting policies [Line Items]
Assets	508		508		517
Total liabilities	448		448		464
Debt	259		259		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	24,706		24,706		24,639
Total liabilities	14,444		14,444		13,700
Debt	8,165		8,165		8,195
Cash held at consolidated affiliated partnerships and restricted cash	916		916		1,151
Cash and cash equivalents | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	35		35		42
Cash held at consolidated affiliated partnerships and restricted cash | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	889		889		989
Investments [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	8,681		8,681		9,207
Due from brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	2,152		2,152		858
Accounts receivable, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	16		16		35
Inventories, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	47		47		48
Property, plant and equipment, net [Member]
Accounting policies [Line Items]
Financing lease right-of-use asset	71		71		77
Property, plant and equipment, net [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	1,090		1,090		1,123
Unrealized gain on derivative contracts | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	1,921		1,921		182
Intangible assets, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	241		241		251
Other assets [Member]
Accounting policies [Line Items]
Operating lease right-of-use asset	595		595		624
Other assets [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	33		33		49
Accounts Payable [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	24		24		25
Accrued expenses and other liabilities
Accounting policies [Line Items]
Operating lease liability	616		616		647
Accrued expenses and other liabilities | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	43		43		98
Unrealized loss on derivative contracts | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	81		81		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	459		459		1,190
Due to brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	2,938		2,938		54
Debt
Accounting policies [Line Items]
Financing lease liability	86		86		93
Debt | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	$ 633		$ 633		$ 633
Icahn Enterprises Holdings
Accounting policies [Line Items]
Percentage of equity ownership in operating subsidiary			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%