Investments (Consolidated Variable Interest Entities - Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Variable Interest Entity [Line Items]
Financial or other support to investees designated as VIEs			$ 0	$ 0
Consolidated Securitization Entities [Member]
Variable Interest Entity [Line Items]
Variable interest, maximum exposure to loss in consolidated securitization entities	110		110		92
Long-term debt held by consolidated securitization entities, percentage range minimum			2.25%	2.25%
Long-term debt held by consolidated securitization entities, percentage range maximum			5.57%	5.57%
Interest expense on long-term debt held by consolidated securitization entities	$ 30	$ 40	$ 96	$ 125