Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Mr. Icahn and affiliates
Related Party Transaction [Line Items]
Percentage fair value of investments in Funds that is attributable to Mr. Icahn	60.00%		59.00%
Mr. Icahn and affiliates | Investment in funds
Related Party Transaction [Line Items]
Amount of transaction with related party	$ 280	$ 600
Mr. Icahn and affiliates | Investment balance in funds
Related Party Transaction [Line Items]
Related party transaction, balance	4,900		$ 4,400
Consolidated VIE | Expense sharing arrangement
Related Party Transaction [Line Items]
Amount of transaction with related party	1	2
Hertz | Receipts and revenue from related party
Related Party Transaction [Line Items]
Amount of transaction with related party	6
Hertz | Payments to and purchases from related party
Related Party Transaction [Line Items]
Amount of transaction with related party	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	$ 2	$ 1