Significant Accounting Policies (Nature of Operations and Basis of Presentation) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) Bank
Significant Accounting Policies [Line Items]
Minimum Number of Days Past Due as to Interest or Principal Payments in Accruing Loans Moves to Nonperforming Loans	90 days
Nature of Operations and Basis of Presentation
Number of banks through which company operates	1
Number of regional banking units Chemical Bank operates through	4
Percentage of FHLB advances secured by first lien real estate residential loans	140.00%
Minimum percentage of tax benefit is recognized for the amount likely to be realized	50.00%
Reserve for contingent income tax liabilities recorded | $	$ 0