Segment Reporting, Income Statements (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		$ 6,815	$ 9,722	$ 10,576
Other revenues from operations		608	666	647
Net (loss) gain from investment activities		(1,421)	(1,931)	322
Interest and dividend income		169	265	148
(Loss) gain on disposition of assets, net		(17)	253	84
Other income (loss), net		(31)	19
Total revenues		6,123	8,994	11,777
Cost of goods sold/Other expenses from operations		6,320	8,205	8,993
Other expenses from operations		487	528	538
Selling, general and administrative		1,191	1,375	1,386
Restructuring, net		10	18	21
Impairment		11	2	92
Interest expense		688	605	524
Total Expenses		8,707	10,733	11,554
Income (loss) from continuing operations before income tax (expense) benefit		(2,584)	(1,739)	223
Income tax benefit (expense)		116	(20)	14
Net income (loss) from continuing operations		(2,468)	(1,759)	237
Less: net income (loss) from continuing operations attributable to non-controlling interests		(815)	(693)	475
Net income (loss) from continuing operations attributable to Icahn Enterprises		(1,653)	(1,066)	(238)
Capital expenditures		199	250	272
Depreciation and amortization		510	519	508
Investment Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		0
Other revenues from operations		0
Net (loss) gain from investment activities		(1,368)	(1,599)	635
Interest and dividend income		136	190	104
(Loss) gain on disposition of assets, net		0
Other income (loss), net		(17)	(5)	(2)
Total revenues		(1,249)	(1,414)	737
Cost of goods sold/Other expenses from operations		0
Other expenses from operations		0
Selling, general and administrative		2	23	12
Restructuring, net		0
Impairment		0
Interest expense		196	106	46
Total Expenses		198	129	58
Income (loss) from continuing operations before income tax (expense) benefit		(1,447)	(1,543)	679
Income tax benefit (expense)		0
Net income (loss) from continuing operations		(1,447)	(1,543)	679
Less: net income (loss) from continuing operations attributable to non-controlling interests		(682)	(768)	360
Net income (loss) from continuing operations attributable to Icahn Enterprises		(765)	(775)	319
Capital expenditures		0
Depreciation and amortization		0
Energy Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		3,930	6,364	7,124
Other revenues from operations		0
Net (loss) gain from investment activities		34
Interest and dividend income		10	4	2
(Loss) gain on disposition of assets, net		(7)	4	(6)
Other income (loss), net		(1)	13	15
Total revenues		3,966	6,385	7,135
Cost of goods sold/Other expenses from operations		4,164	5,707	6,508
Other expenses from operations		0
Selling, general and administrative		116	146	138
Restructuring, net		0		5
Impairment		0
Interest expense		125	106	104
Total Expenses		4,405	5,959	6,755
Income (loss) from continuing operations before income tax (expense) benefit		(439)	426	380
Income tax benefit (expense)		112	(112)	(46)
Net income (loss) from continuing operations		(327)	314	334
Less: net income (loss) from continuing operations attributable to non-controlling interests		(133)	68	121
Net income (loss) from continuing operations attributable to Icahn Enterprises		(194)	246	213
Capital expenditures		124	121	102
Depreciation and amortization		343	352	339
Automotive Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		1,929	2,293	2,295
Other revenues from operations		549	591	563
Net (loss) gain from investment activities		0
Interest and dividend income		0
(Loss) gain on disposition of assets, net		(6)	(4)	(1)
Other income (loss), net		(7)	15	(1)
Total revenues		2,465	2,895	2,856
Cost of goods sold/Other expenses from operations		1,344	1,615	1,493
Other expenses from operations		449	474	483
Selling, general and administrative		904	1,032	1,051
Restructuring, net		8	6	5
Impairment		0		90
Interest expense		12	20	16
Total Expenses		2,717	3,147	3,138
Income (loss) from continuing operations before income tax (expense) benefit		(252)	(252)	(282)
Income tax benefit (expense)		54	55	52
Net income (loss) from continuing operations		(198)	(197)	(230)
Less: net income (loss) from continuing operations attributable to non-controlling interests		0
Net income (loss) from continuing operations attributable to Icahn Enterprises		(198)	(197)	(230)
Capital expenditures		35	47	66
Depreciation and amortization		95	98	92
Food Packaging Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		409	385	395
Other revenues from operations		0
Net (loss) gain from investment activities		0
Interest and dividend income		0		1
(Loss) gain on disposition of assets, net		0
Other income (loss), net		(6)	(8)	(17)
Total revenues		403	377	379
Cost of goods sold/Other expenses from operations		327	312	316
Other expenses from operations		0
Selling, general and administrative		52	55	57
Restructuring, net		1	8	9
Impairment		0	1
Interest expense		11	17	16
Total Expenses		391	393	398
Income (loss) from continuing operations before income tax (expense) benefit		12	(16)	(19)
Income tax benefit (expense)		(8)	(6)	4
Net income (loss) from continuing operations		4	(22)	(15)
Less: net income (loss) from continuing operations attributable to non-controlling interests		0	(5)	(3)
Net income (loss) from continuing operations attributable to Icahn Enterprises		4	(17)	(12)
Capital expenditures		19	17	25
Depreciation and amortization		27	26	26
Metals Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		313	340	466
Other revenues from operations		0
Net (loss) gain from investment activities		0
Interest and dividend income		0
(Loss) gain on disposition of assets, net		1	1
Other income (loss), net		3		1
Total revenues		317	341	467
Cost of goods sold/Other expenses from operations		298	343	441
Other expenses from operations		0
Selling, general and administrative		16	15	19
Restructuring, net		1	3
Impairment		1	1	1
Interest expense		1	1
Total Expenses		317	363	461
Income (loss) from continuing operations before income tax (expense) benefit		0	(22)	6
Income tax benefit (expense)		0		(1)
Net income (loss) from continuing operations		0	(22)	5
Less: net income (loss) from continuing operations attributable to non-controlling interests		0
Net income (loss) from continuing operations attributable to Icahn Enterprises		0	(22)	5
Capital expenditures		3	24	21
Depreciation and amortization		18	19	18
Real Estate Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		43	23	22
Other revenues from operations		59	75	84
Interest and dividend income		1	1	16
(Loss) gain on disposition of assets, net	$ 89	(5)		89
Other income (loss), net			4	1
Total revenues		98	103	212
Cost of goods sold/Other expenses from operations		35	18	18
Other expenses from operations		38	54	54
Selling, general and administrative		34	21	22
Impairment		7
Interest expense				1
Total Expenses		114	93	95
Income (loss) from continuing operations before income tax (expense) benefit		(16)	10	117
Income tax benefit (expense)			6	(5)
Net income (loss) from continuing operations		(16)	16	112
Net income (loss) from continuing operations attributable to Icahn Enterprises		(16)	16	112
Capital expenditures		11	22	13
Depreciation and amortization		17	17	19
Home Fashion Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		188	187	171
Other revenues from operations		0
Net (loss) gain from investment activities		0
Interest and dividend income		0
(Loss) gain on disposition of assets, net		0
Other income (loss), net		2	(1)
Total revenues		190	186	171
Cost of goods sold/Other expenses from operations		150	159	144
Other expenses from operations		0
Selling, general and administrative		43	42	34
Restructuring, net		0	1	2
Impairment		3		1
Interest expense		1	1	1
Total Expenses		197	203	182
Income (loss) from continuing operations before income tax (expense) benefit		(7)	(17)	(11)
Income tax benefit (expense)		0
Net income (loss) from continuing operations		(7)	(17)	(11)
Less: net income (loss) from continuing operations attributable to non-controlling interests		0
Net income (loss) from continuing operations attributable to Icahn Enterprises		(7)	(17)	(11)
Capital expenditures		5	5	5
Depreciation and amortization		8	7	8
Pharma Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		3
Other revenues from operations		0
Net (loss) gain from investment activities		0
Interest and dividend income		0
(Loss) gain on disposition of assets, net		0
Other income (loss), net		0
Total revenues		3
Cost of goods sold/Other expenses from operations		2
Other expenses from operations		0
Selling, general and administrative		2
Restructuring, net		0
Impairment		0
Interest expense		0
Total Expenses		4
Income (loss) from continuing operations before income tax (expense) benefit		(1)
Income tax benefit (expense)		0
Net income (loss) from continuing operations		(1)
Less: net income (loss) from continuing operations attributable to non-controlling interests		0
Net income (loss) from continuing operations attributable to Icahn Enterprises		(1)
Capital expenditures		0
Depreciation and amortization		2
Mining Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		0	130	103
Other revenues from operations		0
Net (loss) gain from investment activities		0
Interest and dividend income		0	1	1
(Loss) gain on disposition of assets, net		0	252	(3)
Other income (loss), net		0	(1)	5
Total revenues		0	382	106
Cost of goods sold/Other expenses from operations		0	51	73
Other expenses from operations		0
Selling, general and administrative		0	15	27
Restructuring, net		0
Impairment		0
Interest expense		0	4	3
Total Expenses		0	70	103
Income (loss) from continuing operations before income tax (expense) benefit		0	312	3
Income tax benefit (expense)		0	(1)	(2)
Net income (loss) from continuing operations		0	311	1
Less: net income (loss) from continuing operations attributable to non-controlling interests		0	12	(2)
Net income (loss) from continuing operations attributable to Icahn Enterprises		0	299	3
Capital expenditures		0	14	40
Depreciation and amortization		0		6
Railcar Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		0
Other revenues from operations		0
Net (loss) gain from investment activities		0
Interest and dividend income		0
(Loss) gain on disposition of assets, net		0		5
Other income (loss), net		0
Total revenues		0		5
Cost of goods sold/Other expenses from operations		0
Other expenses from operations		0		1
Selling, general and administrative		0		1
Restructuring, net		0
Interest expense		0
Total Expenses		0		2
Income (loss) from continuing operations before income tax (expense) benefit		0		3
Income tax benefit (expense)		0		(2)
Net income (loss) from continuing operations		0		1
Less: net income (loss) from continuing operations attributable to non-controlling interests		0
Net income (loss) from continuing operations attributable to Icahn Enterprises		0		1
Capital expenditures		0
Depreciation and amortization		0
Holding Company
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales/Other revenue from operations		0
Other revenues from operations		0
Net (loss) gain from investment activities		(87)	(332)	(313)
Interest and dividend income		22	69	24
(Loss) gain on disposition of assets, net		0
Other income (loss), net		(5)	2	(2)
Total revenues		(70)	(261)	(291)
Cost of goods sold/Other expenses from operations		0
Other expenses from operations		0
Selling, general and administrative		22	26	25
Restructuring, net		0
Impairment		0
Interest expense		342	350	337
Total Expenses		364	376	362
Income (loss) from continuing operations before income tax (expense) benefit		(434)	(637)	(653)
Income tax benefit (expense)		(42)	38	14
Net income (loss) from continuing operations		(476)	(599)	(639)
Less: net income (loss) from continuing operations attributable to non-controlling interests		0		(1)
Net income (loss) from continuing operations attributable to Icahn Enterprises		(476)	$ (599)	$ (638)
Capital expenditures		2
Depreciation and amortization		$ 0