Loans and Leases - Summary of Non-Performing Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Troubled debt restructurings	$ 48	$ 53
Non-Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	79	75
Troubled debt restructurings	21	23
Total non-performing loans	100	98
Other real estate owned	35	41
Total non-performing assets	$ 135	$ 139
Non-performing loans / total loans and leases	0.45%	0.47%
Non-performing loans OREO / total loans and leases OREO	0.61%	0.66%
Non-performing assets / total assets	0.41%	0.44%