Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Mr. Icahn and affiliates | Investment in funds
Related Party Transaction [Line Items]
Amount of transaction with related party			$ 70	$ 280
Related party transaction, balance	$ 4,700		$ 4,700		$ 5,000
Percentage fair value of investments in Funds that is attributable to Mr. Icahn	50.00%		50.00%		50.00%
Consolidated VIE | Expense sharing arrangement
Related Party Transaction [Line Items]
Amount of transaction with related party	$ 2	$ 2	$ 5	2
Hertz (equity method investee) | Receipts and revenue from related party
Related Party Transaction [Line Items]
Amount of transaction with related party	13	12	25	18
Hertz (equity method investee) | Payments to and purchases from related party
Related Party Transaction [Line Items]
Amount of transaction with related party			1	1
ACF | Payments to and purchases from related party
Related Party Transaction [Line Items]
Amount of transaction with related party		1		2
Insight Portfolio Group LLC | Buying group operating expenses
Related Party Transaction [Line Items]
Amount of transaction with related party	0	1	1	2
767 Leasing | Automotive Segment
Related Party Transaction [Line Items]
Assets at non-consolidated VIE	105		105		$ 60
Liabilities at non-consolidated VIE	0		0		1
Investment in non-consolidated VIE during the period	20	$ 5	45	10
Investment balance in non-consolidated VIE as of end of period period	$ 107		$ 107		$ 59
Investment [Member] | Hertz (equity method investee) | Payments to and purchases from related party
Related Party Transaction [Line Items]
Amount of transaction with related party				$ 36