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, 2025	Dec. 31, 2024
Financing Receivable, Impaired
Total portfolio loans and leases	$ 800	$ 622
Commercial
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	563	395
Commercial | Commercial and industrial loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	493	325
Commercial | Commercial mortgage owner-occupied loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	47	63
Commercial | Commercial mortgage nonowner-occupied loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	7	4
Commercial | Commercial construction loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	0	1
Commercial | Commercial leases
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	16	2
Residential Mortgage
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	136	131
Consumer
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	101	96
Consumer | Home equity
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	66	66
Consumer | Indirect secured consumer loans
Financing Receivable, Impaired
Loans and leases receivable, allowance for amortized cost basis	$ 35	$ 30