Bank Premises and Equipment (Bank Premises and Equipment (Parenthetical) (Detail)) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment
Land and improvements	[1]	$ 586	$ 644

[1] (a) At December 31, 2018 and 2017 , land and improvements, buildings and construction in progress included $55 and $91, respectively, associated with parcels of undeveloped land intended for future branch expansion.