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	Jun. 30, 2022		Mar. 31, 2022	Dec. 31, 2021		Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	$ 161			$ 164
Collectively evaluated	1,853			1,728
Total ALLL	2,014	[1]	$ 1,908	1,892	[1]	$ 2,033	$ 2,208	$ 2,453
Individually evaluated	1,449			1,352
Collectively evaluated	117,241			110,544
Total portfolio loans and leases	118,690			111,896
Leveraged leases	246			285
Commercial Leveraged Leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Total ALLL	2			2
Leveraged leases	246			285
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	65			77
Collectively evaluated	1,100			1,025
Total ALLL	1,165		1,110	1,102		1,224	1,329	1,456
Individually evaluated	576			579
Collectively evaluated	74,474			69,689
Total portfolio loans and leases	75,050			70,268
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	52			46
Collectively evaluated	196			189
Total ALLL	248		239	235		235	247	294
Individually evaluated	563			460
Collectively evaluated	16,870			15,783
Total portfolio loans and leases	17,433			16,243
Residential mortgage loans	133			154		151
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated	44			41
Collectively evaluated	557			514
Total ALLL	601		$ 559	555		$ 574	$ 632	$ 703
Individually evaluated	310			313
Collectively evaluated	25,897			25,072
Total portfolio loans and leases	$ 26,207			$ 25,385

[1] Includes $21 and $24 of other short-term investments, $267 and $322 of portfolio loans and leases, $(3) and $(2) of ALLL, $2 and $2 of other assets, $10 and $1 of other liabilities, and $200 and $263 of long-term debt from consolidated VIEs that are included in their respective captions above at June 30, 2022 and December 31, 2021, respectively. For further information, refer to Note 12.