Financial Instruments Investment Segment and Holding Company Narrative (Details) - Investment Segment [Member] - Investment Funds [Member] - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Derivative [Line Items]
Maximum payout amounts relating to put options written	$ 6,800		$ 2,500
Open Option Contracts Written, Covered Put Options on Existing Short Positions	6,600		2,400
Fair value of derivative instruments with credit-risk related contingent features in a liability position	641		614
Cash collateral posted for derivative positions	1,400		$ 1,200
Put Option [Member]
Derivative [Line Items]
Realized and unrealized gain (loss) on derivatives, net	$ 15	$ (1)