Variable Interest Entities ("VIE's") (Consolidated Variable Interest Entity Settlement Payments and Mark-to-Market Adjustments) (Details) (Derivative Instruments Not Designated And Not Qualifying As Hedging Instruments [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Consolidated Variable Interest Entity Settlement Payments And Mark To Market Adjustments [Line Items]
Gains (losses) for consolidated variable interest entities	$ 15	[1]	$ 69	[1]
Credit Default Swaps [Member]
Consolidated Variable Interest Entity Settlement Payments And Mark To Market Adjustments [Line Items]
Gains (losses) for consolidated variable interest entities	15		71
Contingent Forwards [Member]
Consolidated Variable Interest Entity Settlement Payments And Mark To Market Adjustments [Line Items]
Gains (losses) for consolidated variable interest entities			$ (2)

[1] Reported in realized gain (loss) on our Consolidated Statements of Comprehensive Income (Loss).