Loans and Leases and the Allowance for Credit Losses - Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 2,191	$ 1,975	$ 2,129	$ 1,925
Provision for credit losses	150	150	350	270
Charge-offs	180	162	343	257
Recoveries	43	35	68	60
Net charge-offs	(137)	(127)	(275)	(197)
Ending balance	2,204	1,998	2,204	1,998
Commercial and industrial
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	684	579	620	568
Provision for credit losses	176	12	313	33
Charge-offs	78	24	156	44
Recoveries	8	16	13	26
Net charge-offs	(70)	(8)	(143)	(18)
Ending balance	790	583	790	583
Commercial Real Estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	754	669	764	611
Provision for credit losses	(70)	122	(61)	208
Charge-offs	43	99	68	128
Recoveries	17	2	23	3
Net charge-offs	(26)	(97)	(45)	(125)
Ending balance	658	694	658	694
Residential Real Estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	118	113	116	115
Provision for credit losses	(8)	3	(6)	2
Charge-offs	2	1	3	3
Recoveries	2	3	3	4
Net charge-offs	0	2	0	1
Ending balance	110	118	110	118
Consumer:
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	635	614	629	631
Provision for credit losses	52	13	104	27
Charge-offs	57	38	116	82
Recoveries	16	14	29	27
Net charge-offs	(41)	(24)	(87)	(55)
Ending balance	$ 646	$ 603	$ 646	$ 603