Acquired Property Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Acquired Property [Roll Forward]
Beginning balance - Acquired property	$ 10,348	$ 12,744	$ 11,442	$ 12,307
Additions - Acquired property	2,431	3,425	5,366	7,197
Disposals - Acquired property	(3,580)	(3,873)	(7,609)	(7,208)
Ending balance - Acquired property	9,199	12,296	9,199	12,296
Real Estate Owned Valuation Allowance [Roll Forward]
Beginning balance - Valuation allowance	(830)	(784)	(824)	(686)
Decrease (increase) in Valuation allowance	137	48	131	(50)
Ending balance - Valuation allowance	(693)	(736)	(693)	(736)
Ending balance - Acquired property, net	$ 8,506	$ 11,560	$ 8,506	$ 11,560	$ 10,618