Bank Premises and Equipment (Detail) - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Bank Premises And Equipment [Abstract]
Land and improvements	[1]	$ 713	$ 793
Buildings		1,750	1,807
Equipment		1,683	1,682
Leasehold improvements		411	416
Construction in Progress		78	98
Land and improvements held for sale		58	23
Buildings held for sale		17	3
Equipment held for sale		3
Leasehold improvements held for sale		3
Accumulated depreciation and amortization		(2,452)	(2,357)
Total	[2]	$ 2,264	$ 2,465

[1] At September 30, 2015 and December 31, 2014, land and improvements included $102 million and $165 million, respectively, associated with parcels of undeveloped land intended for future branch expansion.

[2] Includes $81 and $26 of bank premises and equipment held for sale at September 30, 2015 and December 31, 2014, respectively. For further information refer to Note 7.