Regulatory Capital Requirements and Capital Ratios (Details) $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Risk Based Ratios
Banking regulation, capital conservation buffer, capital conserved, minimum	0.025
Fifth Third Bancorp
Risk Based Ratios
CET1 capital (as a percent)	0.1029	0.0928
Tier I risk-based capital (as a percent)	0.1159	0.1053
Total risk-based capital (as a percent)	0.1372	0.1279
Tier I leverage (as a percent)	0.0873	0.0856
Risk Based Capital
CET1 capital	$ 16,800	$ 15,670
Tier I risk-based capital	18,916	17,786
Total risk-based capital	22,400	21,606
Tier I leverage	$ 18,916	$ 17,786
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)	0.1242	0.1131
Tier I risk-based capital (as a percent)	0.1242	0.1131
Total risk-based capital (as a percent)	0.1385	0.1281
Tier I leverage (as a percent)	0.0938	0.0923
Risk Based Capital
CET1 capital	$ 20,147	$ 18,952
Tier I risk-based capital	20,147	18,952
Total risk-based capital	22,463	21,463
Tier I leverage	$ 20,147	$ 18,952
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