Bank Premises & Equipment (Bank Premises and Equipment) (Detail) - USD ($) $ in Millions		Mar. 31, 2018	Dec. 31, 2017
Bank Premises and Equipment
Land and improvements	[1]	$ 636	$ 644
Buildings	[1]	1,661	1,679
Equipment		1,921	1,876
Leasehold improvements		399	399
Construction in progress	[1]	76	93
Land and improvements held for sale		12	17
Buildings held for sale		8	9
Equipment held for sale		0	1
Accumulated depreciation and amortization		(2,747)	(2,715)
Total bank premises and equipment	[2]	$ 1,966	$ 2,003

[1] (a ) At March 31, 2018 and December 31, 2017 , land and improvements , buildings and construction in progress included $ 89 and $ 9 1 , respectively, associated w ith parcels of undeveloped land intended for future branch ex pansion.

[2] Includes $ 20 and $ 27 of bank premises and equipment held for sale at March 31, 2018 and December 31, 2017 , respectively. For further information refer to Note 7 .