Basis of Presentation and Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended		12 Months Ended
	Oct. 31, 2025	Nov. 30, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Line Items]
Total Assets			$ 14,215	$ 16,279	$ 14,215	$ 16,279
Assets held for sale				25		25
Limited partners and general partner			3,426	4,621	$ 3,426	4,621	$ 6,073	$ 9,558
Aggregate general partner ownership interest of parent and operating subsidiary					1.99%
Debt			6,616	6,809	$ 6,616	6,809
Fair value of long-term debt			6,300	6,600	6,300	6,600
Restricted cash			1,969	2,636	1,969	2,636
Owned real estate		$ 465
Portion of inventory under LIFO method			164	168	164	168
Post-retirement benefit liability			24	25	24	25
Impairment			2	0	40		7
Accumulated other comprehensive loss
Accounting Policies [Line Items]
Limited partners and general partner			(49)	(61)	(49)	(61)
TEB LLC
Accounting Policies [Line Items]
Carrying amount of equity method investment					74
Carrying value of equity investment and related party loan receivable					$ 203
Discontinued Operations, Held-for-Sale
Accounting Policies [Line Items]
Assets held for sale				25		25
Icahn Enterprises Holdings
Accounting Policies [Line Items]
Percentage of equity ownership in operating subsidiary					99.00%
Affiliate ownership interest					98.01%
Cash held at consolidated affiliated partnerships
Accounting Policies [Line Items]
Restricted cash			746	915	$ 746	915
Restricted cash
Accounting Policies [Line Items]
Restricted cash			1,200	1,700	1,200	1,700
Primary beneficiary
Accounting Policies [Line Items]
Total Assets			113	108	113	108
Energy
Accounting Policies [Line Items]
Total Assets			4,129	4,751	4,129	4,751
Limited partners and general partner			1,285	1,323	1,285	1,323
Debt			1,765	1,919	1,765	1,919
Remaining performance obligation expected to be recognized as revenue within one year			4		4
Deferred revenue			$ 44	$ 78	44	78
Recorded revenue					50	$ 16	46
Carrying value of property, plant and equipment					$ 93
Lease term			5 years 1 month 6 days	5 years 4 months 24 days	5 years 1 month 6 days	5 years 4 months 24 days
Automotive Segment
Accounting Policies [Line Items]
Total Assets			$ 1,248	$ 1,939	$ 1,248	$ 1,939
Limited partners and general partner			455	1,099	455	1,099
Debt			21	31	21	31
Restricted cash			8	8	8	8
Deferred revenue			28	$ 37	28	37
Recorded revenue					$ 20	$ 22	$ 22
Impairment of long-lived assets held-for-use	$ 23
Impairment, Long-Lived Asset, Held-for-Use, Statement of Income or Comprehensive Income [Extensible Enumeration]	Asset Impairment Charges
Impairment		$ 2	$ 2
Lease term			5 years	5 years 4 months 24 days	5 years	5 years 4 months 24 days
Real Estate and Automotive | Minimum
Accounting Policies [Line Items]
Lease term			5 years		5 years
Real Estate and Automotive | Maximum
Accounting Policies [Line Items]
Lease term			39 years		39 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Accounting Policies [Line Items]
Remaining performance obligation for contracts with an original expected duration of more than one year			1 year		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 | Energy
Accounting Policies [Line Items]
Remaining performance obligation expected to be recognized as revenue within one year			$ 3		$ 3