Credit Quality (Summarizes the Bancorp's Recorded Investment in Impaired Loans and Related Allowance by Class) (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 1,635	$ 1,382
Commercial Portfolio Segment | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	23	60
Commercial Portfolio Segment | Troubled Debt Restructuring On Non accrual Status
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	231	147
Residential Mortgage Loans | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	735	724
Residential Mortgage Loans | Troubled Debt Restructuring On Non accrual Status
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	79	12
Consumer Portfolio Segment [Member] | Troubled Debt Restructuring On Accrual Status
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	230	237
Consumer Portfolio Segment [Member] | Troubled Debt Restructuring On Non accrual Status
Financing Receivable, Impaired [Line Items]
Unpaid Principal Balance	$ 72	$ 41