(Details) - USD ($) $ in Millions						1 Months Ended				3 Months Ended		12 Months Ended
	Jul. 31, 2019	Jan. 29, 2019	Dec. 05, 2018	Oct. 01, 2018	Aug. 01, 2018	Aug. 31, 2018	Jan. 31, 2018	Aug. 31, 2017	Jan. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Description of Business [Line Items]
Affiliate ownership interest												98.01%
Purchase of additional interests in consolidated subsidiaries												$ 241	$ 5	$ 349
Gain on disposition of assets, net												253	84	2,163
Proceeds from disposition of assets												505	3,370	1,983
Seller financing secured mortgages resulting from disposition of assets												0	0	375
Energy Segment
Description of Business [Line Items]
Gain on disposition of assets, net												4	(6)	(3)
Automotive Segment
Description of Business [Line Items]
Gain on disposition of assets, net												(4)	(1)	5
Food Packaging Segment
Description of Business [Line Items]
Gain on disposition of assets, net												0	0	0
Real Estate Segment
Description of Business [Line Items]
Gain on disposition of assets, net						$ 89		$ 456				0	89	496
Proceeds from disposition of assets						$ 179		225
Seller financing secured mortgages resulting from disposition of assets								375
Total consideration received from sale of asset								600
Real Estate Segment | First Mortgage
Description of Business [Line Items]
Seller financing secured mortgages resulting from disposition of assets								345
Real Estate Segment | Second Mortgage
Description of Business [Line Items]
Seller financing secured mortgages resulting from disposition of assets								$ 30
Railcar Segment
Description of Business [Line Items]
Gain on disposition of assets, net												0	5	1,664
Mining Segment
Description of Business [Line Items]
Gain on disposition of assets, net												$ 252	(3)	0
Icahn Enterprises Holdings
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary												99.00%
Gain on disposition of assets, net												$ 253	84	2,163
Proceeds from disposition of assets												505	3,370	1,983
Investment Funds
Description of Business [Line Items]
Fair value of investment in subsidiary										$ 4,300	$ 5,100	$ 4,300	$ 5,100
CVR Refining | Energy Segment
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary		3.90%
Common units validly tendered and not properly withdrawn					21,625,106
Purchase of additional interests in consolidated subsidiaries		$ 241
CVR Partners | Energy Segment
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary												34.40%
CVR Energy | Energy Segment
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary		80.60%										70.80%
Equity issued to acquire additional interest in consolidated subsidiary (number of units)					13,699,549
Change in equity as a result of acquisition of additional interest in consolidated subsidiary					$ 99
Viskase | Food Packaging Segment
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary												78.60%	74.60%
Proceeds from rights offering							$ 50
Contribution to subsidiary							$ 44
ARL | Railcar Segment
Description of Business [Line Items]
Gain on disposition of assets, net													$ 5	1,700
Proceeds from disposition of assets													$ 17
aggregate consideration for business disposed of														$ 1,800
Ferrous Resources | Mining Segment
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary	77.20%
Gain on disposition of assets, net												$ 252
Proceeds from disposition of assets												$ 463
Aggregate consideration for business to be disposed of			$ 550
Federal-Mogul
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary													100.00%	82.00%
Purchase of additional interests in consolidated subsidiaries									$ 305
Gain on disposition of assets, net										$ 251
Proceeds from disposition of assets				$ 800
consideration in shares for business disposed of				29,500,000
consideration in non-voting shares for business disposed of				23,800,000
consideration in voting shares for business disposed of				5,700,000
investment, ownership percentage				9.90%
fair market value of shares obtained as consideration for business disposed of				$ 1,200
Tropicana
Description of Business [Line Items]
Percentage of equity ownership in operating subsidiary													83.90%	72.50%
Purchase of additional interests in consolidated subsidiaries														$ 95
Gain on disposition of assets, net											779
Proceeds from disposition of assets				1,500
aggregate consideration for business disposed of				$ 1,800
Subsidiary repurchase of treasury stock														36
ARI
Description of Business [Line Items]
Gain on disposition of assets, net											$ 400
Proceeds from disposition of assets			$ 831
ADS and Precision Tune | Automotive Segment
Description of Business [Line Items]
Payments to acquire businesses														$ 162
Mr. Icahn and affiliates
Description of Business [Line Items]
Affiliate ownership interest												92.00%
Icahn Enterprises G.P.
Description of Business [Line Items]
General partner ownership percentage in Icahn Enterprises												1.00%
Aggregate general partner ownership interest of parent and operating subsidiary												1.99%
Icahn Enterprises G.P. | Icahn Enterprises Holdings
Description of Business [Line Items]
General partner ownership percentage in Icahn Enterprises												1.00%