Schedule I - Condensed Financial Information of Parent - Statements of Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	$ (2,468)	$ (1,791)	$ 2,001
Adjustments to reconcile net (loss) income to net cash used in operating activities:
(Gain) loss on disposition of assets	17	(253)	(84)
Net loss (gain) from securities transactions	926	(570)	476
Other, net	60	16	123
Net cash used in operating activities	(416)	(1,460)	923
Other, net	(1)		8
Net cash (used in) provided by investing activities	(581)	586	2,587
Partnership contributions	102	55
Proceeds from borrowings	1,946	810	1,268
Net cash provided by (used in) financing activities	(653)	566	(157)
Net change in cash and cash equivalents and restricted cash and restricted cash equivalents	(1,654)	(393)	3,427
Cash and cash equivalents and restricted cash and restricted cash equivalents, beginning of period	4,945	5,338	1,911
Cash and cash equivalents and restricted cash and restricted cash equivalents, end of period	3,291	4,945	5,338
Icahn Enterprises (Parent)
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	(1,653)	(1,098)	1,482
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Equity in loss (income) of subsidiary	1,307	750	(1,819)
(Gain) loss on extinguishment of debt	4	(2)
Other, net	(23)	(25)	1
Net cash used in operating activities	(365)	(375)	(336)
Net investment in and advances from subsidiaries	1,276	(363)	433
Net cash (used in) provided by investing activities	1,276	(363)	433
Partnership distributions	(526)	(112)	(97)
Partnership contributions	102	55
Proceeds from borrowings	866	2,507
Repayments of borrowings	(1,350)	(1,700)
Debt issuance costs and other	(3)	(12)
Net cash provided by (used in) financing activities	(911)	738	(97)
Icahn Enterprises Holdings (Parent)
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	(1,652)	(1,097)	1,483
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Equity in loss (income) of subsidiary	1,237	363	(2,200)
(Gain) loss on disposition of assets	(7)	(2)	(23)
Net loss (gain) from securities transactions	63	377	389
Other, net		(1)
Change in operating assets and liabilities	(23)	45	8
Net cash used in operating activities	(382)	(315)	(343)
Net advances from subsidiaries	1,093	567	238
Net proceeds from the disposition of fixed assets	(7)
Other, net	23		41
Net cash (used in) provided by investing activities	1,123	567	279
Partnership distributions	(526)	(112)	(97)
Partnership contributions	102	55
Proceeds from borrowings	866	2,507
Repayments of borrowings	(1,350)	(1,700)	(21)
Debt issuance costs and other	(3)	(12)
Net cash provided by (used in) financing activities	(911)	738	(118)
Net change in cash and cash equivalents and restricted cash and restricted cash equivalents	(170)	990	(182)
Cash and cash equivalents and restricted cash and restricted cash equivalents, beginning of period	1,049	59	241
Cash and cash equivalents and restricted cash and restricted cash equivalents, end of period	$ 879	$ 1,049	$ 59