Securities (Schedule of Credit Losses on Other-than-Temporarily Impaired Non-agency RMBS where Portion of the Unrealized Loss was Recognized in OCI (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Securities
Balance at beginning of period	$ 72	$ 86	$ 78	$ 98
Credit losses on securities without previous OTTI	0	0	1	0
Credit losses on securities with previously recognized OTTI	4		4
Reductions for securities sold/settled during the period	(5)	(4)	(11)	(16)
Credit recoveries through yield	(1)	0	(2)	0
Balance at end of period	$ 70	$ 82	$ 70	$ 82