Changes in the Servicing Rights (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Servicing Rights at Fair Value
Carrying amount before valuation allowance as of the beginning of the period	$ 1,392	$ 1,440
Servicing rights that result from the transfer of residential mortgage loans	63	73
Amortization	(140)	(121)	$ (168)
Other-than-temporary impairment	111
Carrying amount before valuation allowance as of the end of the period	1,204	1,392	1,440
Valuation allowance for servicing rights:
Beginning balance	(534)	(469)
(Provision for) recovery of MSR impairment	4	(65)
Other-than-temporary impairment	111
Ending balance	(419)	(534)	$ (469)
Carrying amount as of the end of the period	$ 785	$ 858