Credit Quality and the Allowance for Loan and Lease Losses - Summary of Recorded Investment in Portfolio Loans and Leases by Age and Class (Details) - USD ($) $ in Millions		Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	[1],[2]	$ 112,050	$ 108,782
Commercial
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		70,268	68,997
90 Days Past Due and Still Accruing		19	48
Commercial | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		70,132	68,640
Commercial | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		136	357
Commercial | 30-89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		81	171
Commercial | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		55	186
Commercial | Commercial and industrial loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		51,659	49,665
90 Days Past Due and Still Accruing		17	39
Loans and leases related to SBA Paycheck Protection Program of CARES Act		1,300	4,800
Commercial | Commercial and industrial loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		51,549	49,421
Commercial | Commercial and industrial loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		110	244
Commercial | Commercial and industrial loans | 30-89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		61	119
Loans and leases related to SBA Paycheck Protection Program of CARES Act		20
Commercial | Commercial and industrial loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		49	125
Loans and leases related to SBA Paycheck Protection Program of CARES Act		6
Commercial | Commercial mortgage owner-occupied loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		4,709	4,675
90 Days Past Due and Still Accruing		1	7
Commercial | Commercial mortgage owner-occupied loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		4,701	4,645
Commercial | Commercial mortgage owner-occupied loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		8	30
Commercial | Commercial mortgage owner-occupied loans | 30-89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		4	7
Commercial | Commercial mortgage owner-occupied loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		4	23
Commercial | Commercial mortgage nonowner-occupied loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		5,607	5,927
90 Days Past Due and Still Accruing		0	1
Commercial | Commercial mortgage nonowner-occupied loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		5,606	5,860
Commercial | Commercial mortgage nonowner-occupied loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		1	67
Commercial | Commercial mortgage nonowner-occupied loans | 30-89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		0	31
Commercial | Commercial mortgage nonowner-occupied loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		1	36
Commercial | Commercial construction loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		5,241	5,815
90 Days Past Due and Still Accruing		1	0
Commercial | Commercial construction loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		5,241	5,808
Commercial | Commercial construction loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		0	7
Commercial | Commercial construction loans | 30-89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		0	7
Commercial | Commercial construction loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		0	0
Commercial | Commercial leases
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		3,052	2,915
90 Days Past Due and Still Accruing		0	1
Commercial | Commercial leases | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		3,035	2,906
Commercial | Commercial leases | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		17	9
Commercial | Commercial leases | 30-89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		16	7
Commercial | Commercial leases | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases		$ 1	$ 2

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

[2] 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.