Bank Premises and Equipment (Bank Premises and Equipment (Parenthetical) (Detail)) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment
Land and improvements	[1]	$ 663	$ 685
Branches and undeveloped parcels of land
Property, Plant and Equipment
Land and improvements		$ 92	$ 102

[1] (a) At December 31, 2016 and 2015 , land and improvements, buildings and construction in progress included $ 92 and $ 102 , respectively, associated with parcels of undeveloped land intended for future branch expansion.