Other Assets Held for Sale - MSR Activity (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Discontinued Operations and Disposal Groups [Abstract]
Beginning balance	$ 117	$ 140	$ 140	$ 159
Changes in fair value due to changes in valuation model inputs or assumptions	(8)	19	(24)	8
Reductions related to customer payments	(5)	(1)	(12)	(9)
Ending balance	$ 104	$ 158	$ 104	$ 158