Regulatory Capital Requirements and Capital Ratios (Details) $ in Millions	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Risk Based Ratios
Banking regulation, capital conservation buffer, capital conserved, minimum	0.032	0.025
Fifth Third Bancorp
Risk Based Ratios
CET1 capital (as a percent)	0.1057	0.1029
Tier I risk-based capital (as a percent)	0.1186	0.1159
Total risk-based capital (as a percent)	0.1386	0.1372
Tier I leverage (as a percent)	0.0922	0.0873
Risk Based Capital
CET1 capital	$ 17,339	$ 16,800
Tier I risk-based capital	19,455	18,916
Total risk-based capital	22,746	22,400
Tier I leverage	$ 19,455	$ 18,916
Fifth Third Bancorp | Well-Capitalized
Risk Based Ratios
Tier I risk-based capital (as a percent)	0.0600
Total risk-based capital (as a percent)	0.1000
Fifth Third Bancorp | Minimum
Risk Based Ratios
CET1 capital (as a percent)	0.0450
Tier I risk-based capital (as a percent)	0.0600
Total risk-based capital (as a percent)	0.0800
Tier I leverage (as a percent)	0.0400
Fifth Third Bank, National Association
Risk Based Ratios
CET1 capital (as a percent)	0.1286	0.1242
Tier I risk-based capital (as a percent)	0.1286	0.1242
Total risk-based capital (as a percent)	0.1419	0.1385
Tier I leverage (as a percent)	0.1002	0.0938
Risk Based Capital
CET1 capital	$ 20,943	$ 20,147
Tier I risk-based capital	20,943	20,147
Total risk-based capital	23,116	22,463
Tier I leverage	$ 20,943	$ 20,147
Fifth Third Bank, National Association | Well-Capitalized
Risk Based Ratios
CET1 capital (as a percent)	0.0650
Tier I risk-based capital (as a percent)	0.0800
Total risk-based capital (as a percent)	0.1000
Tier I leverage (as a percent)	0.0500
Fifth Third Bank, National Association | Minimum
Risk Based Ratios
CET1 capital (as a percent)	0.0450
Tier I risk-based capital (as a percent)	0.0600
Total risk-based capital (as a percent)	0.0800
Tier I leverage (as a percent)	0.0400