Income Taxes Narrative (Details) - USD ($) $ in Millions		12 Months Ended
	Aug. 01, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 09, 2020	Dec. 08, 2020	Dec. 31, 2017
Income Tax Contingency [Line Items]
Book basis of net assets		$ 3,382	$ 5,456
Book/tax basis difference		(774)	(1,397)
Tax basis of net assets		2,608	4,059
Domestic income (loss) from continuing operations before taxes		(2,586)	(1,765)	$ 235
Foreign income (loss) from continuing operations before taxes		2	26	(12)
Income before income tax benefit (expense)		(2,584)	(1,739)	223
Current income tax (expense) benefit		67	(109)	(15)
Deferred income tax (expense) benefit		49	89	29
Income tax (expense) benefit		116	(20)	14
Deferred tax assets, Property, plant and equipment		17	17
Deferred tax asset, net operating loss		996	791
deferred tax asset, Tax credits		60	29
Deferred Tax Assets, Capital Loss Carryforwards		358	155
Deferred tax assets, lease arrangements		141	133
Deferred tax asset, Other		119	71
Deferred tax assets, gross		1,691	1,196
Deferred Tax Assets, Valuation Allowance		(1,026)	(619)
Deferred Tax Assets, Net of Valuation Allowance		665	577
Deferred tax liabilities, Property, plant and equipment		(121)	(125)
Deferred tax liabilities, Intangible assets		(84)	(37)
Deferred tax liability, Investment in partnerships		(657)	(652)
Deferred tax liabilities, Investment in U.S. subsidiaries		(184)	(184)
Deferred Tax Liabilities, Leases		(135)	(125)
Deferred tax liabilities, Other		(46)	(61)
Deferred Tax Liabilities, Gross		(1,227)	(1,184)
Deferred tax liabilities, net of deferred tax assets		(562)	(607)
Deferred Tax Assets, Net		7	32
Deferred tax liability		569	639
Increase (decrease) in deferred tax asset valuation amount		$ 407
Deferred Tax Carryforward Period		5 years
Undistributed earnings of foreign subsidiaries			66
Additional tax due from GILTI		$ 1
Unrecognized tax benefits balance		35	33	34			$ 34
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		31	27	30
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		3	1	1
Income tax expense related to interest and penalties related to unrecognized tax benefits		2	0	(1)
Deferred tax assets, lease arrangements		141	133
Deferred Tax Liabilities, Leasing Arrangements		135	125
Energy Segment
Income Tax Contingency [Line Items]
Income before income tax benefit (expense)		(439)	426	380
Income tax (expense) benefit		112	(112)	(46)
Icahn Enterprises Holdings
Income Tax Contingency [Line Items]
Book basis of net assets		3,380	5,453
Book/tax basis difference		(774)	(1,397)
Tax basis of net assets		2,606	4,056
Income before income tax benefit (expense)		(2,583)	(1,738)	224
Income tax (expense) benefit		116	(20)	14
Deferred tax liability		569	639
American Entertainment Properties Corp.
Income Tax Contingency [Line Items]
Deferred tax assets, Operating loss carryforwards, Subject to expiration			2,100
American Entertainment Properties Corp. | Viskase Companies, Inc
Income Tax Contingency [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent					89.00%	79.00%
CVR Energy
Income Tax Contingency [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit			2
CVR Energy | Energy Segment
Income Tax Contingency [Line Items]
Equity issued to acquire additional interest in consolidated subsidiary (number of units)	13,699,549
CVR Refining | Energy Segment
Income Tax Contingency [Line Items]
Common units validly tendered and not properly withdrawn	21,625,106
Domestic tax authority
Income Tax Contingency [Line Items]
Current income tax (expense) benefit		69	(106)	(11)
Deferred income tax (expense) benefit		51	87	30
Foreign tax authority
Income Tax Contingency [Line Items]
Current income tax (expense) benefit		(2)	(3)	(4)
Deferred income tax (expense) benefit		(2)	2	$ (1)
Foreign tax authority | American Entertainment Properties Corp.
Income Tax Contingency [Line Items]
Deferred tax assets, Operating loss carryforwards, Subject to expiration		11
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration		29
Kansas | CVR Energy
Income Tax Contingency [Line Items]
Tax credits			$ 30
United States | Vivus
Income Tax Contingency [Line Items]
Tax credits		17
Operating loss carryforwards		$ 656