Credit Quality and the Allowance for Loan and Lease Losses - Summary of the Amortized Cost Basis of the Bancorp's Collateral Dependent Loans (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Impaired
Total portfolio loans and leases	$ 741	$ 594
Commercial
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	492	346
Commercial \| Commercial and industrial loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	350	322
Commercial \| Commercial mortgage owner-occupied loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	68	19
Commercial \| Commercial mortgage nonowner-occupied loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	12	5
Commercial \| Commercial construction loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	62	0
Residential Mortgage
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	143	143
Consumer
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	106	105
Consumer \| Home equity
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	70	70
Consumer \| Indirect secured consumer loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	$ 36	$ 35