Regulatory Capital Requirements and Capital Ratios (Details) $ in Millions	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Fifth Third Bancorp
Risk Based Ratios
CET1 capital (as a percent)	0.0954	0.1034
Tier I risk-based capital (as a percent)	0.1091	0.1183
Total risk-based capital (as a percent)	0.1342	0.1508
Tier I leverage (as a percent)	0.0827	0.0849
Risk Based Capital
CET1 capital	$ 14,781	$ 14,682
Tier I risk-based capital	16,897	16,797
Total risk-based capital	20,789	21,412
Tier I leverage	$ 16,897	$ 16,797
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)	0.1090	0.1228
Tier I risk-based capital (as a percent)	0.1090	0.1228
Total risk-based capital (as a percent)	0.1233	0.1417
Tier I leverage (as a percent)	0.0829	0.0885
Risk Based Capital
CET1 capital	$ 16,723	$ 17,253
Tier I risk-based capital	16,723	17,253
Total risk-based capital	18,917	19,915
Tier I leverage	$ 16,723	$ 17,253
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