Intangible Assets - Residential MSRs Activity (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair value of MSRs:
Beginning balance	$ 186	$ 225	$ 227	$ 168
Additions related to loan sales	0	3	0	14
Changes in fair value due to:
Change in valuation model inputs or assumptions	2	4	(22)	73
Customer payments	(6)	(8)	(23)	(31)
Ending balance	$ 182	$ 224	$ 182	$ 224