Loans and Leases - Schedule of Loans by Class (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 138,288	$ 70,781	$ 65,524
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	54,390	53,455
Commercial | Commercial construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,971	2,804
Commercial | Owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	14,456	14,473
Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	10,292	9,902
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	24,508	24,105
Commercial | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,163	2,171
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	17,727	17,326
Consumer | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	13,727	13,309
Consumer | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,916	1,951
Consumer | Consumer auto
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,452	1,414
Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	632	652
SVB
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	66,171	0
SVB | Global fund banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	36,097	0
SVB | Investor dependent - growth stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	1,994	0
SVB | Investor dependent - early stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	4,418	0
SVB | Innovation C&I and cash flow dependent
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9,193	0
SVB | Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	9,476	0
SVB | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	2,444	0
SVB | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases	$ 2,549	$ 0