Credit Quality and the Allowance for Loan and Lease Losses - Summary of the ALLL and Related Loans and Leases Classified by Portfolio Segment (Details) - USD ($) $ in Millions	Sep. 30, 2022		Jun. 30, 2022	Dec. 31, 2021		Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	$ 157			$ 164
Collectively evaluated	1,942			1,728
Total ALLL	2,099	[1]	$ 2,014	1,892	[1]	$ 1,954	$ 2,033	$ 2,453
Individually evaluated	1,419			1,352
Collectively evaluated	118,455			110,544
Total portfolio loans and leases	119,874			111,896
Leveraged leases	248			285
Commercial Leveraged Leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Total ALLL	2			2
Leveraged leases	248			285
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	63			77
Collectively evaluated	1,095			1,025
Total ALLL	1,158		1,165	1,102		1,167	1,224	1,456
Individually evaluated	561			579
Collectively evaluated	75,217			69,689
Total portfolio loans and leases	75,778			70,268
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	50			46
Collectively evaluated	204			189
Total ALLL	254		248	235		235	235	294
Individually evaluated	557			460
Collectively evaluated	16,918			15,783
Total portfolio loans and leases	17,475			16,243
Residential mortgage loans	125			154		156
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	44			41
Collectively evaluated	643			514
Total ALLL	687		$ 601	555		$ 552	$ 574	$ 703
Individually evaluated	301			313
Collectively evaluated	26,320			25,072
Total portfolio loans and leases	$ 26,621			$ 25,385

[1] Includes $19 and $24 of other short-term investments, $223 and $322 of portfolio loans and leases, $(3) and $(2) of ALLL, $2 and $2 of other assets, $9 and $1 of other liabilities, and $156 and $263 of long-term debt from consolidated VIEs that are included in their respective captions above at September 30, 2022 and December 31, 2021, respectively. For further information, refer to Note 12.