Bank Premises & Equipment (Bank Premises and Equipment) (Detail) - USD ($) $ in Millions		Sep. 30, 2018	Dec. 31, 2017
Bank Premises and Equipment
Land and improvements	[1]	$ 597	$ 644
Buildings	[1]	1,593	1,679
Equipment		1,962	1,876
Leasehold improvements		404	399
Construction in progress	[1]	89	93
Land and improvements held for sale		24	17
Branches held for sale		11	9
Equipment held for sale		3	1
Accumulated depreciation and amortization		(2,787)	(2,715)
Total bank premises and equipment	[2]	$ 1,896	$ 2,003

[1] (a ) At September 30, 2018 and December 31, 2017 , land and improvements , buildings and construction in progress included $ 55 and $ 9 1 , respectively, associated w ith parcels of undeveloped land intended for future branch expansion.

[2] Includes $ 38 and $ 27 of bank premises and equipment held for sale at September 30, 2018 and December 31, 2017 , respectively. For further information refer to Note 7 .