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		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated		$ 164		$ 225
Collectively evaluated		1,728		2,228
Total ALLL		1,892	[1]	2,453	[1]	$ 1,202	$ 1,103
Individually evaluated		1,352		1,863
Collectively evaluated		110,544		106,343
Purchased credit deteriorated				415
Total portfolio loans and leases		111,896		108,621
Leveraged leases		285		323
Total	[1],[2]	112,050		108,782
Residential mortgage loans | GNMA loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total				39
Commercial Leveraged Leases
Financing Receivable, Allowance for Credit Loss [Line Items]
Total ALLL		2		3
Leveraged leases		285		323
Commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated		77		114
Collectively evaluated		1,025		1,342
Total ALLL		1,102		1,456		710	645
Individually evaluated		579		962
Collectively evaluated		69,689		67,701
Purchased credit deteriorated				334
Total portfolio loans and leases		70,268		68,997
Total		70,268		68,997
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated		46		68
Collectively evaluated		189		226
Total ALLL		235		294		73	81
Individually evaluated		460		628
Collectively evaluated		15,783		15,073
Purchased credit deteriorated				66
Total portfolio loans and leases		16,243		15,767
Loans		154		161
Residential Mortgage | Residential mortgage loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total		16,243		15,767
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated		41		43
Collectively evaluated		514		660
Total ALLL		555		703		$ 298	$ 267
Individually evaluated		313		273
Collectively evaluated		25,072		23,569
Purchased credit deteriorated				15
Total portfolio loans and leases		25,385		23,857
Total		$ 41,782		39,785
Consumer | Residential mortgage loans | GNMA loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total				$ 39

[1] Includes $24 and $55 of other short-term investments, $322 and $756 of portfolio loans and leases, $(2) and $(7) of ALLL, $2 and $5 of other assets, $1 and $2 of other liabilities and $263 and $656 of long-term debt from consolidated VIEs that are included in their respective captions above at December 31, 2021 and 2020, respectively. For further information, refer to Note 12.

[2] Includes $154 and $161 of residential mortgage loans measured at fair value at December 31, 2021 and 2020, respectively.