VIE (Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses) (Detail) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Fifth Third Community Development Corporation Investments
Variable Interest Entity
Total Assets	$ 1,416	$ 1,435
Total Liabilities	411	428
Maximum Exposure	1,416	1,435
Private equity investments
Variable Interest Entity
Total Assets	89	89
Total Liabilities	0	0
Maximum Exposure	161	164
Lease pool entities
Variable Interest Entity
Total Assets	78	74
Total Liabilities	0	0
Maximum Exposure	78	74
Loans Provided to VIEs
Variable Interest Entity
Total Assets	2,891	2,715
Total Liabilities	0	0
Maximum Exposure	$ 3,987	$ 4,083