Bank Premises and Equipment (Bank Premises and Equipment (Detail)) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment
Land and improvements	[1]	$ 663	$ 685
Buildings	[1]	1,672	1,755
Equipment		1,761	1,696
Leasehold improvements		398	403
Construction in progress	[1]	99	85
Land and improvements held for sale		29	55
Buildings held for sale		9	20
Equipment held for sale		1	3
Leasehold improvements held for sale		0	3
Accumulated depreciation and amortization		(2,567)	(2,466)
Total bank premises and equipment	[2]	$ 2,065	$ 2,239
Building | Upper Limit
Property, Plant and Equipment
Useful life		30 years
Building | Lower limit
Property, Plant and Equipment
Useful life		2 years
Equipment | Upper Limit
Property, Plant and Equipment
Useful life		30 years
Equipment | Lower limit
Property, Plant and Equipment
Useful life		2 years
Leasehold Improvements | Upper Limit
Property, Plant and Equipment
Useful life		30 years
Leasehold Improvements | Lower limit
Property, Plant and Equipment
Useful life		1 year

[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.

[2] Includes $ 39 and $ 81 of bank premises and equipment held for sale at December 31, 2016 and 2015 , respectively. For further information refer to N ote 7 .