Loans and ACL (Changes in Carrying Amount and Accretable Yield for Covered Loans) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Purchased Impaired Loans [Member]
Accretable yield for purchased loans, beginning balance	$ 264	$ 520
Accretion recognized during the period for purchased loans	(149)	(219)
Other, net	72	(37)
Accretable yield for purchased loans, ending balance	187	264
Carrying amount of loans, beginning balance	1,400	2,123
Change in carrying amount of loans, accretion recognized during period	149	219
Change in carrying amount of loans, payments received, net	(686)	(942)
Carrying amount of loans, ending balance	863	1,400
Outstanding UPB at end of period	1,266	2,047
Purchased Nonimpaired Loans [Member]
Accretable yield for purchased loans, beginning balance	617	1,193
Accretion recognized during the period for purchased loans	(301)	(541)
Other, net	35	(35)
Accretable yield for purchased loans, ending balance	351	617
Carrying amount of loans, beginning balance	1,894	2,744
Change in carrying amount of loans, accretion recognized during period	301	541
Change in carrying amount of loans, payments received, net	(1,023)	(1,391)
Carrying amount of loans, ending balance	1,172	1,894
Outstanding UPB at end of period	$ 1,516	$ 2,489