Schedule I Condensed Financial Information of Parent - Statements of Cash Flows (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	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	$ (157)	$ (373)	$ (597)	$ (664)	$ 1,170	$ (158)	$ 577	$ 412	$ (1,791)	$ 2,001	$ 2,632
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Gain on disposition of assets, net									253	84	2,163
Net (gain) loss from securities transactions									(570)	476	(2,273)
Other, net									16	123	(27)
Net cash used in operating activities									(1,460)	923	(1,348)
Other, net									(38)	0	(80)
Net cash provided by investing activities									586	2,587	682
Partnership contributions									55	0	612
Proceeds from subsidiary borrowings									810	1,268	1,334
Net cash provided by (used in) financing activities									566	(157)	369
Net change in cash and cash equivalents and restricted cash and restricted cash equivalents									(393)	3,427	27
Cash and cash equivalents and restricted cash and restricted cash equivalents	4,945				5,338				4,945	5,338	1,911	$ 1,884
Icahn Enterprises (Parent)
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									(1,098)	1,482	2,454
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Equity in (loss) income of subsidiaries									(750)	1,819	2,789
(Gain) loss on extinguishment of debt									(2)	0	2
Other, net									(25)	1	1
Net cash used in operating activities									(375)	(336)	(332)
Net investment in subsidiaries									(363)	433	(210)
Net cash provided by investing activities									(363)	433	(210)
Partnership distributions									(112)	(97)	(81)
Partnership contributions									55	0	612
Proceeds from subsidiary borrowings									2,507	0	2,470
Repayments of subsidiary borrowings									(1,700)	0	(2,450)
Debt issuance costs and other									(12)	0	(9)
Net cash provided by (used in) financing activities									738	(97)	542
Net change in cash and cash equivalents and restricted cash and restricted cash equivalents									0	0	0
Cash and cash equivalents and restricted cash and restricted cash equivalents	0				0				0	0	0	0
Icahn Enterprises Holdings (Parent)
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									(1,097)	1,483	2,456
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Equity in (loss) income of subsidiaries									(363)	2,200	2,763
Gain on disposition of assets, net									(2)	(23)	1
Net (gain) loss from securities transactions									377	389	0
Other, net									(1)	0	(36)
Change in operating assets and liabilities									45	8	18
Net cash used in operating activities									(315)	(343)	(324)
Net investment in subsidiaries									567	238	(97)
Other, net									0	41	53
Net cash provided by investing activities									567	279	(44)
Partnership distributions									(112)	(97)	(81)
Partnership contributions									55	0	612
Proceeds from subsidiary borrowings									2,507	0	2,470
Repayments of subsidiary borrowings									(1,700)	(21)	(2,450)
Debt issuance costs and other									(12)	0	(7)
Net cash provided by (used in) financing activities									738	(118)	544
Net change in cash and cash equivalents and restricted cash and restricted cash equivalents									990	(182)	176
Cash and cash equivalents and restricted cash and restricted cash equivalents	$ 1,049				$ 59				$ 1,049	$ 59	$ 241	$ 65