Loans and Leases - Loan Modification Activities to Borrowers Experiencing Financial Difficulty on Financing Receivables (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 1,586
Percent of total loan class at period end	1.18%
Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 1,511
Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	18
Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	57
Commercial and Industrial [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 198
Percent of total loan class at period end	0.35%
Commercial and Industrial [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 179
Commercial and Industrial [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	18
Commercial and Industrial [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	1
Commercial Real Estate [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 651
Percent of total loan class at period end	2.57%
Commercial Real Estate [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 610
Commercial Real Estate [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	41
Residential Builder and Developer [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 71
Percent of total loan class at period end	6.63%
Residential Builder and Developer [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 71
Other Commercial Construction [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 488
Percent of total loan class at period end	7.34%
Other Commercial Construction [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 480
Other Commercial Construction [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	8
Residential [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 165
Percent of total loan class at period end	0.74%
Residential [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 160
Residential [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	5
Residential Limited Documentation [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 12
Percent of total loan class at period end	1.25%
Residential Limited Documentation [Member] | Payment Deferral [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 11
Residential Limited Documentation [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	1
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 1
Percent of total loan class at period end	0.03%
Home Equity Lines and Loans [Member] | Combination of Modification Types [Member]
Financing Receivable, Modifications other than Troubled Debt Restructuring [Line Items]
Financing receivable, modifications other than troubled debt restructuring	$ 1