Acquired Property Net Held-for-Use (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Foreclosed Properties Acquired Held-for-Use [Roll Forward]
Beginning balance, January 1	$ 256	$ 873	$ 835
Transfers in from held for sale, net and additions	333	544	1,173
Transfers to held for sale, net	(367)	(1,027)	(748)
Depreciation, asset write-downs and other	(87)	(134)	(387)
Ending balance, December 31	$ 135	$ 256	$ 873