Credit Quality and the Allowance for Loan and Lease Losses - Summary of Amortized Cost Basis of Modifications to Borrowers Experiencing Financial Difficulty (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	$ 77
Term Extension
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	52
Interest Rate Reduction
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	11
Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	2
Term Extension and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	11
Term Extension, Interest Rate Reduction and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Commercial Portfolio Segment | Commercial and industrial loans
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	51
Commercial Portfolio Segment | Commercial and industrial loans | Term Extension
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	51
Commercial Portfolio Segment | Commercial and industrial loans | Interest Rate Reduction
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Commercial Portfolio Segment | Commercial and industrial loans | Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Commercial Portfolio Segment | Commercial and industrial loans | Term Extension and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Commercial Portfolio Segment | Commercial and industrial loans | Term Extension, Interest Rate Reduction and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans | Term Extension
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans | Interest Rate Reduction
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans | Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans | Term Extension and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans | Term Extension, Interest Rate Reduction and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Residential mortgage loans
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	14
Residential mortgage loans | Term Extension
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Residential mortgage loans | Interest Rate Reduction
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Residential mortgage loans | Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	2
Residential mortgage loans | Term Extension and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	11
Residential mortgage loans | Term Extension, Interest Rate Reduction and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Consumer | Home equity
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Consumer | Home equity | Term Extension
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Home equity | Interest Rate Reduction
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Consumer | Home equity | Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Home equity | Term Extension and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Home equity | Term Extension, Interest Rate Reduction and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Credit card
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	10
Consumer | Credit card | Term Extension
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Credit card | Interest Rate Reduction
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	10
Consumer | Credit card | Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Credit card | Term Extension and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Credit card | Term Extension, Interest Rate Reduction and Payment Delay
Financing Receivable, Allowance for Credit Losses
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	$ 0