Retirement Plans (Details Textuals) (Details) - USD ($) $ in Millions		6 Months Ended
	Jun. 14, 2019	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer		$ 0
Bank Mutual Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer			$ 31
Huntington National Bank
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Effective Date of Acquisition	Jun. 14, 2019