Loans and Leases and the Allowance for Credit Losses - Changes in Allowance for Credit Losses (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 2,184	$ 2,129
Provision for credit losses	130	200
Charge-offs	(160)	(163)
Recoveries	46	25
Net charge-offs	(114)	(138)
Ending balance	2,200	2,191
Commercial and industrial
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	769	620
Provision for credit losses	22	137
Charge-offs	(50)	(78)
Recoveries	21	5
Net charge-offs	(29)	(73)
Ending balance	762	684
Commercial Real Estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	599	764
Provision for credit losses	30	9
Charge-offs	(22)	(25)
Recoveries	3	6
Net charge-offs	(19)	(19)
Ending balance	610	754
Residential Real Estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	108	116
Provision for credit losses	(3)	2
Charge-offs	(2)	(1)
Recoveries	2	1
Net charge-offs	0	0
Ending balance	105	118
Consumer:
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	708	629
Provision for credit losses	81	52
Charge-offs	(86)	(59)
Recoveries	20	13
Net charge-offs	(66)	(46)
Ending balance	$ 723	$ 635