Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Accounting Policies [Line Items]
Assets	$ 27,973		$ 24,989
Liabilities	17,966		15,731
Carrying value	7,712		8,059
Fair value of long-term debt	7,900		8,200
Cash held at consolidated affiliated partnerships and restricted cash	1,747		1,612
Cash held at consolidated affiliated partnerships
Accounting Policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash	95		686
Restricted cash
Accounting Policies [Line Items]
Cash held at consolidated affiliated partnerships and restricted cash	1,652		926
Energy Segment
Accounting Policies [Line Items]
Assets	4,569		4,723
Liabilities	3,216		2,880
Carrying value	1,676		1,691
Cash held at consolidated affiliated partnerships and restricted cash	7		7
Deferred revenue	34		31
Recorded revenue	30	$ 27
Revenue, remaining performance obligation	7
Revenue, current portion of remaining performance obligation	1
Automotive Segment
Accounting Policies [Line Items]
Assets	2,867		3,085
Liabilities	1,052		1,531
Carrying value	16		368
Cash held at consolidated affiliated partnerships and restricted cash	19		20
Deferred revenue	41		41
Recorded revenue	18	$ 19
Icahn Enterprises Holdings
Accounting Policies [Line Items]
Assets	27,973		24,989
Liabilities	17,967		15,733
Carrying value	7,713		8,061
Cash held at consolidated affiliated partnerships and restricted cash	1,747		1,612
Cash and cash equivalents | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	110		31
Cash held at consolidated affiliated partnerships and restricted cash | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	1,636		1,558
Investments [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	9,653		8,239
Due from brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	5,149		3,437
Accounts receivable, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	33		37
Inventories, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	59		42
Property, plant and equipment, net [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	993		1,042
Unrealized gain on derivative contracts | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	793		785
Intangible assets, net | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	217		232
Other assets [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Assets	59		107
Accounts Payable [Member] | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Liabilities	45		25
Accrued expenses and other liabilities | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Liabilities	91		70
Deferred tax liabilities | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Liabilities	1		1
Unrealized loss on derivative contracts | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Liabilities	476		622
Securities sold, not yet purchased, at fair value | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Liabilities	4,957		2,521
Due to brokers | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Liabilities	1,622		1,618
Debt | Icahn Enterprises Holdings | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Liabilities	$ 625		$ 636
Icahn Enterprises Holdings
Accounting Policies [Line Items]
Percentage of equity ownership in operating subsidiary	99.00%
Viskase | Variable Interest Entity, Primary Beneficiary [Member]
Accounting Policies [Line Items]
Percentage of equity ownership in operating subsidiary	50.00%