LOANS AND LEASES AND ALLOWANCE FOR CREDIT LOSSES - Certain Loans Acquired Balances at Acquisition (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|---|
| FirstMerit Bank | |||
| Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items] | |||
| Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield | $ 33 | $ 37 | $ 0 |
| X | ||||||||||
- Definition Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Details
|