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	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	$ 116,809	$ 110,158
Commercial
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	75,050	70,268
90 Days Past Due and Still Accruing	7	19
Commercial | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	74,885	70,132
Commercial | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	165	136
Commercial | 30 to 89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	121	81
Commercial | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	44	55
Commercial | Commercial and industrial loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	56,095	51,659
90 Days Past Due and Still Accruing	6	17
Loans and leases related to SBA Paycheck Protection Program of CARES Act	371	1,300
Commercial | Commercial and industrial loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	55,952	51,549
Commercial | Commercial and industrial loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	143	110
Commercial | Commercial and industrial loans | 30 to 89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	105	61
Loans and leases related to SBA Paycheck Protection Program of CARES Act	16	20
Commercial | Commercial and industrial loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	38	49
Loans and leases related to SBA Paycheck Protection Program of CARES Act	5	6
Commercial | Commercial mortgage owner-occupied loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	5,063	4,709
90 Days Past Due and Still Accruing	0	1
Commercial | Commercial mortgage owner-occupied loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	5,050	4,701
Commercial | Commercial mortgage owner-occupied loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	13	8
Commercial | Commercial mortgage owner-occupied loans | 30 to 89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	11	4
Commercial | Commercial mortgage owner-occupied loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	2	4
Commercial | Commercial mortgage nonowner-occupied loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	5,685	5,607
90 Days Past Due and Still Accruing	0	0
Commercial | Commercial mortgage nonowner-occupied loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	5,685	5,606
Commercial | Commercial mortgage nonowner-occupied loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	0	1
Commercial | Commercial mortgage nonowner-occupied loans | 30 to 89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	0	0
Commercial | Commercial mortgage nonowner-occupied loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	0	1
Commercial | Commercial construction loans
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	5,357	5,241
90 Days Past Due and Still Accruing	0	1
Commercial | Commercial construction loans | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	5,356	5,241
Commercial | Commercial construction loans | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	1	0
Commercial | Commercial construction loans | 30 to 89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	0	0
Commercial | Commercial construction loans | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	1	0
Commercial | Commercial leases
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	2,850	3,052
90 Days Past Due and Still Accruing	1	0
Commercial | Commercial leases | Current
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	2,842	3,035
Commercial | Commercial leases | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	8	17
Commercial | Commercial leases | 30 to 89 Days
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	5	16
Commercial | Commercial leases | 90 Days or More
Financing Receivable, Recorded Investment, Past Due
Loans and Leases	$ 3	$ 1