Loan Portfolio (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 119,011	$ 119,394
Accrued interest	500	417
Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	82,554	82,465
Accrued interest	365	314
Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	36,457	36,929
Accrued interest	135	103
Commercial and industrial | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	60,059	59,647
Commercial mortgage | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	16,048	16,352
Construction | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,646	2,530
Total commercial real estate loans | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	18,694	18,882
Commercial lease financing | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,801	3,936
Real estate — residential mortgage | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	21,637	21,401
Home equity loans | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	7,529	7,951
Total residential — prime loans | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	29,166	29,352
Consumer direct loans | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,257	6,508
Credit cards | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,001	1,026
Consumer indirect loans | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	33	43
Credit cards | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	200	172
Credit cards | Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,001	1,026
Collateral Pledged | Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5	8
Education Lending | Discontinued operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 381	$ 434