Segment Reporting - Condensed Balance Sheets By Reporting Segment (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
ASSETS
Cash and cash equivalents	$ 2,381	$ 3,794
Cash held at consolidated affiliated partnerships and restricted cash	876	1,151
Investments	8,197	9,945
Accounts receivable, net	472	483
Inventories, net	1,583	1,795
Property, plant and equipment, net	4,416	4,454
Goodwill and intangible assets, net	701	713
Other assets	5,680	2,304
Assets	24,306	24,639
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	6,203	4,315
Securities sold, not yet purchased, at fair value	459	1,190
Debt	8,227	8,192
Total liabilities	14,889	13,697
Equity attributable to Icahn Enterprises	3,635	5,456
Equity attributable to non-controlling interests	5,782	5,486
Total equity	9,417	10,942	$ 11,652	$ 12,980
Liabilities and Equity	24,306	24,639
Investment Segment
ASSETS
Cash and cash equivalents	12	11
Cash held at consolidated affiliated partnerships and restricted cash	851	989
Investments	7,519	9,207
Accounts receivable, net	0	0
Inventories, net	0	0
Property, plant and equipment, net	0	0
Goodwill and intangible assets, net	0	0
Other assets	4,328	1,076
Assets	12,710	11,283
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	3,028	1,310
Securities sold, not yet purchased, at fair value	459	1,190
Debt	0	0
Total liabilities	3,487	2,500
Equity attributable to Icahn Enterprises	4,370	4,296
Equity attributable to non-controlling interests	4,853	4,487
Total equity	9,223	8,783
Liabilities and Equity	12,710	11,283
Energy Segment
ASSETS
Cash and cash equivalents	805	652
Cash held at consolidated affiliated partnerships and restricted cash	0	0
Investments	249	81
Accounts receivable, net	149	182
Inventories, net	211	373
Property, plant and equipment, net	2,866	2,888
Goodwill and intangible assets, net	253	258
Other assets	345	239
Assets	4,878	4,673
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	1,082	1,180
Securities sold, not yet purchased, at fair value	0	0
Debt	1,691	1,195
Total liabilities	2,773	2,375
Equity attributable to Icahn Enterprises	1,187	1,312
Equity attributable to non-controlling interests	918	986
Total equity	2,105	2,298
Liabilities and Equity	4,878	4,673
Automotive Segment
ASSETS
Cash and cash equivalents	51	46
Cash held at consolidated affiliated partnerships and restricted cash	0	0
Investments	120	120
Accounts receivable, net	138	143
Inventories, net	1,168	1,215
Property, plant and equipment, net	904	916
Goodwill and intangible assets, net	379	382
Other assets	565	673
Assets	3,325	3,495
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	1,180	1,340
Securities sold, not yet purchased, at fair value	0	0
Debt	415	405
Total liabilities	1,595	1,745
Equity attributable to Icahn Enterprises	1,730	1,750
Equity attributable to non-controlling interests	0	0
Total equity	1,730	1,750
Liabilities and Equity	3,325	3,495
Food Packaging Segment
ASSETS
Cash and cash equivalents	13	22
Cash held at consolidated affiliated partnerships and restricted cash	1	1
Investments	0	0
Accounts receivable, net	84	78
Inventories, net	102	100
Property, plant and equipment, net	154	161
Goodwill and intangible assets, net	30	30
Other assets	123	125
Assets	507	517
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	197	196
Securities sold, not yet purchased, at fair value	0	0
Debt	260	268
Total liabilities	457	464
Equity attributable to Icahn Enterprises	39	40
Equity attributable to non-controlling interests	11	13
Total equity	50	53
Liabilities and Equity	507	517
Metals Segment
ASSETS
Cash and cash equivalents	1	3
Cash held at consolidated affiliated partnerships and restricted cash	6	6
Investments	0	0
Accounts receivable, net	51	32
Inventories, net	26	32
Property, plant and equipment, net	118	122
Goodwill and intangible assets, net	10	11
Other assets	28	27
Assets	240	233
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	72	70
Securities sold, not yet purchased, at fair value	0	0
Debt	17	7
Total liabilities	89	77
Equity attributable to Icahn Enterprises	151	156
Equity attributable to non-controlling interests	0	0
Total equity	151	156
Liabilities and Equity	240	233
Real Estate Segment
ASSETS
Cash and cash equivalents	56	53
Cash held at consolidated affiliated partnerships and restricted cash	2	2
Investments	15	15
Accounts receivable, net	12	12
Inventories, net	0	0
Property, plant and equipment, net	300	299
Goodwill and intangible assets, net	6	8
Other assets	130	125
Assets	521	514
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	40	38
Securities sold, not yet purchased, at fair value	0	0
Debt	2	2
Total liabilities	42	40
Equity attributable to Icahn Enterprises	479	474
Equity attributable to non-controlling interests	0	0
Total equity	479	474
Liabilities and Equity	521	514
Home Fashion Segment
ASSETS
Cash and cash equivalents	3	1
Cash held at consolidated affiliated partnerships and restricted cash	8	7
Investments	0	0
Accounts receivable, net	38	36
Inventories, net	76	75
Property, plant and equipment, net	68	68
Goodwill and intangible assets, net	23	24
Other assets	22	20
Assets	238	231
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	66	66
Securities sold, not yet purchased, at fair value	0	0
Debt	28	18
Total liabilities	94	84
Equity attributable to Icahn Enterprises	144	147
Equity attributable to non-controlling interests	0	0
Total equity	144	147
Liabilities and Equity	238	231
Holding Company
ASSETS
Cash and cash equivalents	1,440	3,006
Cash held at consolidated affiliated partnerships and restricted cash	8	146
Investments	294	522
Accounts receivable, net	0	0
Inventories, net	0	0
Property, plant and equipment, net	6	0
Goodwill and intangible assets, net	0	0
Other assets	139	19
Assets	1,887	3,693
LIABILITIES AND EQUITY
Accounts payable, accrued expenses and other liabilities	538	115
Securities sold, not yet purchased, at fair value	0	0
Debt	5,814	6,297
Total liabilities	6,352	6,412
Equity attributable to Icahn Enterprises	(4,465)	(2,719)
Equity attributable to non-controlling interests	0	0
Total equity	(4,465)	(2,719)
Liabilities and Equity	$ 1,887	$ 3,693