Credit Quality and the Allowance for Loan and Lease Losses - Summary of Amortized Cost Basis of Loans Modified for Borrowers Experiencing Financial Difficulty and Subsequently Defaulted (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 171	$ 484
Residential Mortgage
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 31	$ 89
% of Total Class	0.18%	0.51%
Residential Mortgage | Payment Deferral
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 3	$ 16
% of Total Class	0.02%	0.09%
Residential Mortgage | Term Extension and Payment Deferral
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 27	$ 69
% of Total Class	0.15%	0.40%
Residential Mortgage | Term Extension, Interest Rate Reduction and Payment Deferral
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 1	$ 4
% of Total Class	0.01%	0.02%
Consumer
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 16	$ 40
% of Total Class	0.06%	0.14%
Consumer | Credit card
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 9	$ 23
% of Total Class	0.50%	1.27%
Consumer | Payment Deferral
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 2	$ 5
Consumer | Payment Deferral | Credit card
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	0	0
Consumer | Term Extension and Payment Deferral
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	1	2
Consumer | Term Extension and Payment Deferral | Credit card
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	0	0
Consumer | Term Extension, Interest Rate Reduction and Payment Deferral
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	2	7
Consumer | Term Extension, Interest Rate Reduction and Payment Deferral | Credit card
Financing Receivable, Modifications
Financing receivable, excluding accrued interest, modified in period, amount	$ 0	$ 0