Discontinued Operations Income From Discontinued Operations (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations	$ 1,376	$ 176	$ 167	$ 45	$ 59	$ 39	$ 88	$ 48	$ 1,764	$ 234	$ 65
Income (loss) from discontinued operations attributable to Icahn Enterprises									1,720	157	(1)
Capital expenditures									125	171	113
Discontinued operations and held for sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales									6,221	7,985	7,771
Other revenues from operations									892	1,095	1,118
Net gain on investment activities									0	2	0
Interest and dividend income									5	9	7
Gain (loss) on disposition of assets, net									65	6	8
Other income, net									19	61	39
Revenue									7,202	9,158	8,943
Cost of goods sold									5,214	6,802	6,581
Other expenses from operations									425	525	528
Selling, general and administrative									879	1,270	1,309
Restructuring, net									13	21	27
Impairment									6	25	123
Interest expense									160	187	186
Costs and expenses									6,697	8,830	8,754
Income (loss) from discontinued operations before gain (loss) on sale and income tax (expense) benefit									505	328	189
Gain (loss) on sale of discontinued operations									1,430	(3)	0
Income (loss) from discontinued operations before income tax (expense) benefit									1,935	325	189
Income tax (expense) benefit									(171)	(91)	(124)
Income (loss) from discontinued operations									1,764	234	65
Less: income from discontinued operations attributable to non-controlling interests									44	77	66
Income (loss) from discontinued operations attributable to Icahn Enterprises									1,720	157	(1)
Capital expenditures									486	676	579
Depreciation and amortization									166	528	488
Federal-Mogul | Discontinued operations and held for sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales									5,993	7,720	7,341
Other revenues from operations									0	0	0
Net gain on investment activities									0	0	0
Interest and dividend income									2	6	4
Gain (loss) on disposition of assets, net									65	7	8
Other income, net									5	31	31
Revenue									6,065	7,764	7,384
Cost of goods sold									4,999	6,553	6,215
Other expenses from operations									0	0	0
Selling, general and administrative									601	862	845
Restructuring, net									13	21	27
Impairment									2	25	17
Interest expense									137	154	150
Costs and expenses									5,752	7,615	7,254
Income (loss) from discontinued operations before gain (loss) on sale and income tax (expense) benefit									313	149	130
Gain (loss) on sale of discontinued operations									251	0	0
Income (loss) from discontinued operations before income tax (expense) benefit									564	149	130
Income tax (expense) benefit									(69)	(33)	(43)
Income (loss) from discontinued operations									495	116	87
Less: income from discontinued operations attributable to non-controlling interests									7	11	24
Income (loss) from discontinued operations attributable to Icahn Enterprises									488	105	63
Capital expenditures									303	393	381
Depreciation and amortization									100	397	375
Tropicana | Discontinued operations and held for sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales									0	0	0
Other revenues from operations									679	898	943
Net gain on investment activities									0	0	0
Interest and dividend income									1	1	1
Gain (loss) on disposition of assets, net									0	(1)	0
Other income, net									1	27	3
Revenue									681	925	947
Cost of goods sold									0	0	0
Other expenses from operations									311	425	460
Selling, general and administrative									238	371	432
Restructuring, net									0	0	0
Impairment									0	0	106
Interest expense									4	11	13
Costs and expenses									553	807	1,011
Income (loss) from discontinued operations before gain (loss) on sale and income tax (expense) benefit									128	118	(64)
Gain (loss) on sale of discontinued operations									779	(3)	0
Income (loss) from discontinued operations before income tax (expense) benefit									907	115	(64)
Income tax (expense) benefit									(89)	(93)	(24)
Income (loss) from discontinued operations									818	22	(88)
Less: income from discontinued operations attributable to non-controlling interests									17	13	14
Income (loss) from discontinued operations attributable to Icahn Enterprises									801	9	(102)
Capital expenditures									58	112	85
Depreciation and amortization									19	73	71
American Railcar Industries | Discontinued operations and held for sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales									228	265	430
Other revenues from operations									213	197	175
Net gain on investment activities									0	2	0
Interest and dividend income									2	2	2
Gain (loss) on disposition of assets, net									0	0	0
Other income, net									13	3	5
Revenue									456	469	612
Cost of goods sold									215	249	366
Other expenses from operations									114	100	68
Selling, general and administrative									40	37	32
Restructuring, net									0	0	0
Impairment									4	0	0
Interest expense									19	22	23
Costs and expenses									392	408	489
Income (loss) from discontinued operations before gain (loss) on sale and income tax (expense) benefit									64	61	123
Gain (loss) on sale of discontinued operations									400	0	0
Income (loss) from discontinued operations before income tax (expense) benefit									464	61	123
Income tax (expense) benefit									(13)	35	(57)
Income (loss) from discontinued operations									451	96	66
Less: income from discontinued operations attributable to non-controlling interests									20	53	28
Income (loss) from discontinued operations attributable to Icahn Enterprises									431	43	38
Depreciation and amortization									$ 47	$ 58	$ 42