Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Accounting policies [Line Items]
Assets	$ 24,306		$ 24,639
Total liabilities	14,889		13,697
Debt	8,227		8,192
Fair value of long-term debt	7,400		7,600
Cash held at consolidated affiliated partnerships and restricted cash	876		1,151
Operating lease right-of-use asset	616		624
Operating lease liability	637		647
Cash held at consolidated affiliated partnerships
Accounting policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash	235		86
Restricted cash
Accounting policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash	641		1,065
Energy Segment
Accounting policies [Line Items]
Assets	4,878		4,673
Total liabilities	2,773		2,375
Debt	1,691		1,195
Cash held at consolidated affiliated partnerships and restricted cash	0		0
Deferred revenue	38		28
Recorded revenue	6	$ 12
Revenue, remaining performance obligation	10
Revenue, current portion of remaining performance obligation	3
Operating lease right-of-use asset	44		48
Operating lease liability	44		48
Automotive Segment
Accounting policies [Line Items]
Assets	3,325		3,495
Total liabilities	1,595		1,745
Debt	415		405
Cash held at consolidated affiliated partnerships and restricted cash	0		0
Deferred revenue	41		42
Recorded revenue	6	$ 6
Operating lease right-of-use asset	492		501
Operating lease liability	516		527
Real Estate Segment
Accounting policies [Line Items]
Assets	521		514
Total liabilities	42		40
Debt	2		2
Cash held at consolidated affiliated partnerships and restricted cash	2		2
Food Packaging Segment
Accounting policies [Line Items]
Assets	507		517
Total liabilities	457		464
Debt	260		268
Cash held at consolidated affiliated partnerships and restricted cash	1		1
Operating lease right-of-use asset	32		34
Operating lease liability	36		38
Icahn Enterprises Holdings
Accounting policies [Line Items]
Assets	24,306		24,639
Total liabilities	14,892		13,700
Debt	8,230		8,195
Cash held at consolidated affiliated partnerships and restricted cash	876		1,151
Cash and cash equivalents | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	61		42
Cash held at consolidated affiliated partnerships and restricted cash | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	851		989
Investments [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	7,519		9,207
Due from brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	1,432		858
Inventories, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	55		48
Property, plant and equipment, net [Member]
Accounting policies [Line Items]
Financing lease right-of-use asset	74		77
Property, plant and equipment, net [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	1,108		1,123
Intangible assets, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	253		258
Other assets [Member]
Accounting policies [Line Items]
Operating lease right-of-use asset	616		624
Other assets [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Assets	2,936		266
Accounts payable, accrued expenses and other liabilities | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	197		1,338
Securities sold, not yet purchased, at fair value | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	459		1,190
Due to brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	2,938		54
Debt
Accounting policies [Line Items]
Financing lease liability	89		93
Debt | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting policies [Line Items]
Total liabilities	$ 634		$ 633
Icahn Enterprises Holdings
Accounting policies [Line Items]
Percentage of equity ownership in operating subsidiary	99.00%