Segment Reporting - Condensed Balance Sheets By Reporting Segment (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
ASSETS
Cash and cash equivalents	$ 1,942	$ 1,679
Cash held at consolidated affiliated partnerships and restricted cash	1,134	1,612
Investments	11,480	8,913
Accounts receivable, net	572	501
Inventories, net	1,559	1,580
Property, plant and equipment, net	4,231	4,228
Goodwill and intangible assets, net	937	954
Other assets	6,442	5,518
Assets	28,297	24,985
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	5,796	5,147
Securities sold, not yet purchased, at fair value	4,863	2,521
Debt	8,056	8,059
Total liabilities	18,715	15,727
Equity attributable to Icahn Enterprises	3,230	3,383
Equity attributable to non-controlling interests	6,352	5,875
Total equity	9,582	9,258	$ 9,417	$ 10,942
Liabilities and Equity	28,297	24,985
Investment Segment
ASSETS
Cash and cash equivalents	15	14
Cash held at consolidated affiliated partnerships and restricted cash	1,078	1,558
Investments	10,926	8,239
Other assets	5,188	4,308
Assets	17,207	14,119
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	2,100	2,256
Securities sold, not yet purchased, at fair value	4,863	2,521
Total liabilities	6,963	4,777
Equity attributable to Icahn Enterprises	4,675	4,283
Equity attributable to non-controlling interests	5,569	5,059
Total equity	10,244	9,342
Liabilities and Equity	17,207	14,119
Energy Segment
ASSETS
Cash and cash equivalents	707	667
Cash held at consolidated affiliated partnerships and restricted cash	7	7
Investments	315	253
Accounts receivable, net	226	178
Inventories, net	378	298
Property, plant and equipment, net	2,774	2,747
Goodwill and intangible assets, net	233	238
Other assets	277	335
Assets	4,917	4,723
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	1,450	1,189
Debt	1,691	1,691
Total liabilities	3,141	2,880
Equity attributable to Icahn Enterprises	1,006	1,039
Equity attributable to non-controlling interests	770	804
Total equity	1,776	1,843
Liabilities and Equity	4,917	4,723
Automotive Segment
ASSETS
Cash and cash equivalents	42	25
Cash held at consolidated affiliated partnerships and restricted cash	18	20
Investments	28	40
Accounts receivable, net	119	109
Inventories, net	962	1,080
Property, plant and equipment, net	845	857
Goodwill and intangible assets, net	370	372
Other assets	679	582
Assets	3,063	3,085
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	1,153	1,163
Debt	352	368
Total liabilities	1,505	1,531
Equity attributable to Icahn Enterprises	1,558	1,554
Total equity	1,558	1,554
Liabilities and Equity	3,063	3,085
Food Packaging Segment
ASSETS
Cash and cash equivalents	13	16
Accounts receivable, net	86	88
Inventories, net	89	89
Property, plant and equipment, net	152	160
Goodwill and intangible assets, net	29	31
Other assets	102	103
Assets	471	487
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	163	182
Debt	156	151
Total liabilities	319	333
Equity attributable to Icahn Enterprises	139	142
Equity attributable to non-controlling interests	13	12
Total equity	152	154
Liabilities and Equity	471	487
Metals Segment
ASSETS
Cash and cash equivalents		1
Cash held at consolidated affiliated partnerships and restricted cash	2	2
Accounts receivable, net	73	63
Inventories, net	33	22
Property, plant and equipment, net	81	82
Goodwill and intangible assets, net	9	9
Other assets	35	38
Assets	233	217
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	72	73
Debt	28	16
Total liabilities	100	89
Equity attributable to Icahn Enterprises	133	128
Total equity	133	128
Liabilities and Equity	233	217
Real Estate Segment
ASSETS
Cash and cash equivalents	27	21
Cash held at consolidated affiliated partnerships and restricted cash	10	8
Investments	15	15
Accounts receivable, net	11	10
Property, plant and equipment, net	308	310
Goodwill and intangible assets, net		1
Other assets	123	121
Assets	494	486
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	50	45
Debt	1	1
Total liabilities	51	46
Equity attributable to Icahn Enterprises	443	440
Total equity	443	440
Liabilities and Equity	494	486
Home Fashion Segment
ASSETS
Cash and cash equivalents	2	2
Cash held at consolidated affiliated partnerships and restricted cash	3	6
Accounts receivable, net	28	33
Inventories, net	86	81
Property, plant and equipment, net	64	65
Goodwill and intangible assets, net	21	21
Other assets	20	19
Assets	224	227
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	64	65
Debt	23	21
Total liabilities	87	86
Equity attributable to Icahn Enterprises	137	141
Total equity	137	141
Liabilities and Equity	224	227
Pharma Segment
ASSETS
Cash and cash equivalents	2	8
Accounts receivable, net	29	20
Inventories, net	11	10
Goodwill and intangible assets, net	275	282
Other assets	5	6
Assets	322	326
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	52	64
Total liabilities	52	64
Equity attributable to Icahn Enterprises	270	262
Total equity	270	262
Liabilities and Equity	322	326
Holding Company
ASSETS
Cash and cash equivalents	1,134	925
Cash held at consolidated affiliated partnerships and restricted cash	16	11
Investments	196	366
Property, plant and equipment, net	7	7
Other assets	13	6
Assets	1,366	1,315
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	692	110
Debt	5,805	5,811
Total liabilities	6,497	5,921
Equity attributable to Icahn Enterprises	(5,131)	(4,606)
Total equity	(5,131)	(4,606)
Liabilities and Equity	$ 1,366	$ 1,315