VIE (Assets and Liabilities Related to Non-consolidated VIEs and Maximum Exposure to Losses) (Detail) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fifth Third Community Development Corporation Investments
Variable Interest Entity
Total Assets	$ 1,198	$ 1,264
Total Liabilities	376	355
Maximum Exposure	1,198	1,264
Private equity investments
Variable Interest Entity
Total Assets	41	102
Total Liabilities	0	0
Maximum Exposure	73	150
Loans Provided to VIEs
Variable Interest Entity
Total Assets	2,331	1,845
Total Liabilities	0	0
Maximum Exposure	$ 3,617	$ 2,910