Investments Investment Segment (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Investments		$ 9,945				$ 8,337				$ 9,945	$ 8,337
Securities sold, not yet purchased, at fair value		1,190				468				1,190	468
Total Assets		24,639				23,489				24,639	23,489
Total liabilities		13,697				10,509				13,697	10,509
Total revenues		2,621	$ 2,320	$ 2,196	$ 1,855	2,802	$ 2,569	$ 3,423	$ 2,983	8,992	11,777	$ 12,619
Net income (loss) attributable to Icahn Enterprises		(157)	$ (49)	$ (498)	$ (394)	930	$ 118	$ 302	$ 132	(1,098)	1,482	2,454
Investment Segment
Schedule of Investments [Line Items]
Investments		9,207				6,867				9,207	6,867
Securities sold, not yet purchased, at fair value		1,190				468				1,190	468
Portion of unrealized (losses) gains that relates to equity and debt securities still held										706	(800)	1,413
Fair value of equity method investment under fair value option		3,137				1,981				3,137	1,981
Unrealized gain on equity method investments under fair value option										265	667	370
Total Assets		11,283				10,750				11,283	10,750
Total liabilities		2,500				649				2,500	649
Total revenues										(1,414)	737	297
Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		9,062				6,686				9,062	6,686
Investment Segment | Debt securities
Schedule of Investments [Line Items]
Investments		145				181				145	181
Basic materials | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		281				414				281	414
Securities sold, not yet purchased, at fair value		209				0				209	0
Consumer, non-cyclical | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		2,085				2,161				2,085	2,161
Securities sold, not yet purchased, at fair value		29				57				29	57
Consumer, cyclical | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		2,427				1,161				2,427	1,161
Securities sold, not yet purchased, at fair value		379				106				379	106
Energy | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		1,717				1,598				1,717	1,598
Securities sold, not yet purchased, at fair value		124				305				124	305
Financial | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		0				167				0	167
Securities sold, not yet purchased, at fair value		152				0				152	0
Industrial | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Securities sold, not yet purchased, at fair value		217				0				217	0
Technology | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		2,425				1,040				2,425	1,040
Other sectors | Investment Segment | Equity securities
Schedule of Investments [Line Items]
Investments		127				145				127	145
Securities sold, not yet purchased, at fair value		$ 80				0				$ 80	0
Hertz | Investment Segment
Schedule of Investments [Line Items]
Ownership percentage in equity method investment	[1]	24.60%								24.60%
Fair value of equity method investment under fair value option		$ 551				320				$ 551	320
Unrealized gain on equity method investments under fair value option										105	(197)	13
Total Assets		24,627				21,382				24,627	21,382
Total liabilities		22,739				20,262				22,739	20,262
Equity attributable to Icahn Enterprises		$ 1,888				1,120				1,888	1,120
Total revenues										9,779	9,504	8,803
Net income (loss) attributable to Icahn Enterprises										$ (58)	(225)	327
Caesars | Investment Segment
Schedule of Investments [Line Items]
Ownership percentage in equity method investment	[1]	13.40%								13.40%
Fair value of equity method investment under fair value option		$ 1,243				0				$ 1,243	0
Unrealized gain on equity method investments under fair value option										478	0	0
Total Assets		25,300								25,300
Total liabilities		23,100								23,100
Equity attributable to Icahn Enterprises		$ 2,200								2,200
Total revenues										8,700
Net income (loss) attributable to Icahn Enterprises										$ (1,200)
Herbalife | Investment Segment
Schedule of Investments [Line Items]
Ownership percentage in equity method investment	[1]	19.10%								19.10%
Fair value of equity method investment under fair value option		$ 1,343				1,661				$ 1,343	1,661
Unrealized gain on equity method investments under fair value option										(318)	864	357
Total Assets		2,679				2,790				2,679	2,790
Total liabilities		3,069				3,513				3,069	3,513
Equity attributable to Icahn Enterprises		$ (390)				$ (723)				(390)	(723)
Total revenues										4,877	4,892	4,428
Net income (loss) attributable to Icahn Enterprises										$ 311	$ 297	$ 214

[1] Voting interest represents our share of the voting common stock currently held as of December 31, 2019; however, voting common stock held by Mr. Icahn and his affiliates (excluding us) are not included.