Loans and Leases - Summary of Current, Past Due and Nonaccrual Loans (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 132,122	$ 129,492
30-89 Days Past Due	1,724	1,779
Accruing Loans Past Due 90 Days or More	339	491
Nonaccrual	2,166	2,439
Loans and leases, net of unearned discount	134,068	131,564
Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	129,839	126,855
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	238	498
Accruing Loans Past Due 90 Days or More	11	76
Nonaccrual	670	504
Loans and leases, net of unearned discount	57,010	51,920
Commercial and Industrial [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	56,091	50,842
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	311	261
Accruing Loans Past Due 90 Days or More	25	65
Nonaccrual	869	1,240
Loans and leases, net of unearned discount	25,277	26,679
Commercial [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	24,072	25,113
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	5	9
Nonaccrual	3	1
Loans and leases, net of unearned discount	1,073	1,315
Residential Builder and Developer [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,065	1,305
Other Commercial Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	159	240
Accruing Loans Past Due 90 Days or More	1
Nonaccrual	171	125
Loans and leases, net of unearned discount	6,653	7,302
Other Commercial Construction [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,322	6,937
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	763	596
Accruing Loans Past Due 90 Days or More	295	345
Nonaccrual	215	272
Loans and leases, net of unearned discount	22,353	22,705
Residential [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	21,080	21,492
Residential Limited Documentation [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	31	22
Nonaccrual	55	78
Loans and leases, net of unearned discount	911	1,051
Residential Limited Documentation [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	825	951
Home Equity Lines and Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	40	31
Nonaccrual	81	85
Loans and leases, net of unearned discount	4,649	5,007
Home Equity Lines and Loans [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,528	4,891
Recreational Finance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,935
30-89 Days Past Due	87	55
Nonaccrual	36	45
Loans and leases, net of unearned discount	10,058	9,074
Recreational Finance [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,935	8,974
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-89 Days Past Due	60	44
Nonaccrual	14	40
Loans and leases, net of unearned discount	3,992	4,477
Automobile [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	3,918	4,393
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,003
30-89 Days Past Due	30	23
Accruing Loans Past Due 90 Days or More	7	5
Nonaccrual	52	49
Loans and leases, net of unearned discount	2,092	2,034
Other [Member] | Current [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 2,003	$ 1,957