Loans and ACL - Summary of TDRs (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	$ 855	$ 2,200
ALLL attributable to TDRs		152
Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		1,986
Nonperforming TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	180	214
Commercial: | Commercial and industrial
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	441
Commercial: | Commercial and industrial | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		136
Commercial: | CRE
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	174
Commercial: | CRE | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		5
Commercial: | Commercial construction
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	1
Commercial: | Commercial construction | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		1
Consumer: | Residential mortgage
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	203
Consumer: | Residential mortgage | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		1,252
Consumer: | Home equity
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	3
Consumer: | Home equity | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		51
Consumer: | Indirect auto
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	21
Consumer: | Indirect auto | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		462
Consumer: | Other consumer
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	7
Consumer: | Other consumer | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		31
Consumer: | Student | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		30
Credit card
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring	$ 5
Credit card | Performing TDRs
Financing Receivable [Line Items]
Financing Receivable, Troubled Debt Restructuring		$ 18