Loans and Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2023		Jun. 30, 2022	Jun. 30, 2023		Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022		Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable
Unearned income	$ 262			$ 262				$ 238
Net premium	226			226				146
Accrued interest receivable	566			566				518
Direct financing lease - interest income	7		$ 7	13		$ 15
Sales type lease - interest income	16		12	31		23
Allowance for loan and lease losses	2,327	[1]	$ 2,014	2,327	[1]	$ 2,014	$ 2,215	2,194	[1]	$ 1,908	$ 1,892
Commercial Leases
Accounts, Notes, Loans and Financing Receivable
Allowance for loan and lease losses	19			19				15
Federal Home Loan Bank Advances
Accounts, Notes, Loans and Financing Receivable
Loans pledged	15,800			15,800				15,900
FRB Loan
Accounts, Notes, Loans and Financing Receivable
Loans pledged	$ 55,400			$ 55,400				$ 57,100

[1] Includes $1 and $17 of other short-term investments, $42 and $185 of portfolio loans and leases, $(1) and $(2) of ALLL, $0 and $2 of other assets, $9 and $9 of other liabilities, and $37 and $118 of long-term debt from consolidated VIEs that are included in their respective captions above at June 30, 2023 and December 31, 2022, respectively. For further information, refer to Note 11.