Premises and Equipment - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Operating Leases, Rent Expense, Net	$ 202	$ 200	$ 206
Depreciation, Depletion and Amortization	179	175	176
Amortization Of Deferred Gain On Sale Lease Back Of Premises	43	54	$ 53
Sale Leaseback Transaction, Deferred Gain, Gross	$ 67	$ 108