Significant Accounting Policies (Details) $ / shares in Units, $ in Millions	Jan. 25, 2016 USD ($) $ / shares	Jun. 30, 2016 banking_offices
Accounting Policies [Abstract]
Number of branches \| banking_offices		359
The Huntington National Bank \| FirstMerit
Business Acquisition [Line Items]
Share Price	$ 8.80
Business Combination, Consideration Transferred \| $	$ 3,400
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Issued, Per Share	$ 1.72
Business Combination, Cash Consideration, Per Share	5.00
Business Acquisition, Share Price	$ 20.14

Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Issued, Per Share

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- Definition

Business Combination, Cash Consideration, Per Share

+ References

No definition available.

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- Definition

Number of branches.

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- References

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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.

+ References

No definition available.

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- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

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No definition available.

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- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

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Price of a single share of a number of saleable stocks of a company.

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No definition available.

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