Retirement and Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
The estimated net actuarial loss for the defined benefit pension plans that will be amortized from accumulated other comprehensive income into net periodic benefit cost		$ (10)
The increase in pension expense by lowering both the expected rate of return on the plan and the discount rate by 0.25%		1
Defined Benefit Plan Expected Future Benefit Payments in 2016		19
Defined Benefit Plan Expected Future Benefit Payments in 2017		18
Defined Benefit Plan Expected Future Benefit Payments in 2018		17
Defined Benefit Plan Expected Future Benefit Payments in 2019		16
Defined Benefit Plan Expected Future Benefit Payments in 2020		16
Defined Benefit Plan Expected Future Benefit Payments in 2021 through 2025		79
Estimated future defined benefit plan contributions		3
Plan assets managed	[1]	166	$ 195
Profit sharing plan expense		323	334	$ 357
Net underfunded status		(54)	(52)
Change in Mortality Assumption
Defined Benefit Plan Disclosure [Line Items]
Mortality assumption PBO increase (decrease)		(3)
Fifth Third Bank
Defined Benefit Plan Disclosure [Line Items]
Plan assets managed through collective funds		166	195
Non-qualified defined contribution plan
Defined Benefit Plan Disclosure [Line Items]
Expenses recognized for the Bancorp's defined contribution plan		3	2	2
Qualified defined contribution plan
Defined Benefit Plan Disclosure [Line Items]
Expenses recognized for the Bancorp's defined contribution plan		71	44	43
Deferred Profit Sharing
Defined Benefit Plan Disclosure [Line Items]
Expenses recognized for the Bancorp's defined contribution plan			19	$ 32
Common Stock
Defined Benefit Plan Disclosure [Line Items]
Plan assets managed		$ 4	$ 4

[1] For further information on fair value hierarchy levels, refer to Note 1.