Bank Premises and Equipment (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Bank Premises And Equipment [Abstract]
Land and improvements	$ 826	$ 838
Buildings	1,779	1,763
Equipment	1,647	1,581
Leasehold improvements	406	397
Construction in Progress	98	118
Accumulated depreciation and amortization	(2,265)	(2,166)
Total	$ 2,491	$ 2,531