Acquired Property Net (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	Dec. 31, 2013
Acquired Property [Roll Forward]
Acquired Property, Beginning Balance	$ 12,296	$ 10,806	$ 12,307	$ 11,158
Acquired Property, Additions	3,240	4,535	10,437	12,504
Acquired Property, Disposals	(3,412)	(3,397)	(10,620)	(11,718)
Acquired Property, Ending Balance	12,124	11,944	12,124	11,944
Real Estate Owned Valuation Allowance [Roll Forward]
Valuation Allowance, Beginning Balance	(736)	(540)	(686)	(669)
Valuation Allowance, Period (Increase) Decrease	(49)	(24)	(99)	105
Valuation Allowance, Ending Balance	(785)	(564)	(785)	(564)
Acquired property, net	$ 11,339	$ 11,380	$ 11,339	$ 11,380	$ 11,621