Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Loss Contingencies [Line Items]
Defined benefit plan underfunded amount	$ 371		$ 371		$ 424
Mr. Icahn and affiliates
Loss Contingencies [Line Items]
Affiliate ownership interest			91.50%
Starfire Holding Corporation
Loss Contingencies [Line Items]
Ownership percentage by Mr. Icahn	99.40%		99.40%
Pension funding indemnity agreement with subsidiary	$ 250		$ 250
Energy Segment
Loss Contingencies [Line Items]
RINs costs	20	$ 64	47	$ 164
Biofuel blending obligation	7		7		28
RINs asset	4		4
Automotive Segment
Loss Contingencies [Line Items]
Accrued environmental liabilities					16
Railcar Segment
Loss Contingencies [Line Items]
Railcar loss contingency accrual	9		9
Federal-Mogul
Loss Contingencies [Line Items]
Defined benefit plan underfunded amount	294		294
Federal-Mogul | Automotive Segment
Loss Contingencies [Line Items]
Estimated litigation liability	56		56
Estimated litigation liability, interest accrued	6		6
Capital contribution to subsidiary	56		$ 56
Federal-Mogul Products, Inc. | Automotive Segment
Loss Contingencies [Line Items]
Payments made in connection with litigation	3
Icahn Enterprises G.P. | Mr. Icahn and affiliates
Loss Contingencies [Line Items]
Affiliate ownership in parent company general partner			100.00%
ACF
Loss Contingencies [Line Items]
Defined benefit plan underfunded amount	77		$ 77
Accrued expenses and other liabilities
Loss Contingencies [Line Items]
Accrued environmental liabilities	38		38		$ 34
Liabilities held for sale
Loss Contingencies [Line Items]
Accrued environmental liabilities	$ 16		$ 16