Credit Quality and the Allowance for Loan and Lease Losses - Summary of Loans That Were Modified for Borrowers Experiencing Financial Difficulty (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	$ 77
Term Extension
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	52
Commercial Portfolio Segment | Commercial and industrial loans
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	51
Commercial Portfolio Segment | Commercial and industrial loans | Term Extension
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	51
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Commercial Portfolio Segment | Commercial mortgage owner-occupied loans | Term Extension
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Residential mortgage loans
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	14
Residential mortgage loans | Term Extension
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Home equity
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	1
Consumer | Home equity | Term Extension
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	0
Consumer | Credit card
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	10
Consumer | Credit card | Term Extension
Financing Receivable, Recorded Investment, Past Due
Amortized cost basis of the modifications to borrowers experiencing financial difficulty	$ 0