Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2017

New Accounting Pronouncements and Changes in Accounting Principles [Abstract]

Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]

Accounting Policy Elections

Effective January 1, 2017, residential mortgage loans that are classified as held for sale are accounted using the fair value option method of accounting. The Corporation has elected the fair value option to mitigate accounting mismatches between held for sale loan valuations and corresponding derivative commitments. Prior to January 1, 2017,residential mortgage loans that were classified as held for sale were accounted for at the lower of cost or market method (“LOCOM”) of accounting.

New Accounting Pronouncements, Policy [Policy Text Block]

New Accounting Pronouncements Adopted

Standard	Description	Date of adoption	Effect on financial statements
ASU 2017-08 Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities	The amendments of the new standard require that certain purchased callable debt securities held at a premium be amortized to the earliest call date. The amendments do not require an accounting change for securities held at a discount, which continue to be amortized to maturity.	1st Quarter 2017	The Corporation early adopted with no material impact on results of operations, financial position, or liquidity.
ASU 2017-03 Accounting Changes and Error Corrections (Topic 250) and Investments - Equity Method and Joint Ventures (Topic 323)	The standard states that for ASUs which have not been adopted yet, the registrant needs to determine the potential effects (if material) of those ASUs on the financial statements when adopted and include the appropriate disclosures in the financial statements. If the impact of adoption is unknown or cannot be estimated, the registrant should include a statement noting this and consider adding qualitative disclosures to the financial statements to assist the reader in evaluating the impact of the ASUs, when adopted, on the financial statements.	1st Quarter 2017	No material impact on results of operations, financial position, or liquidity.
ASU 2016-17 Consolidation (Topic 810): Interests Held through Related Parties That Are under Common Control	The FASB issued an amendment to address how a reporting entity that is a single decision maker of a variable interest entity treats indirect interests in the entity held through related parties that are under common control with the reporting entity.	1st Quarter 2017	No material impact on results of operations, financial position, or liquidity.
ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting	The FASB issued an amendment involving several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. Entities should apply the amendment related to the timing of when excess tax benefits are recognized, minimum statutory withholding requirements, forfeitures, and intrinsic value using a modified retrospective transition method by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is adopted. Entities should apply the amendment related to the presentation of employee taxes paid on the statement of cash flows when an employer withholds shares to meet the minimum statutory withholding requirement retrospectively. The amendment requiring recognition of excess tax benefits and tax deficiencies in the income statement and the practical expedient for estimating expected term should be applied prospectively.	4th Quarter 2016	The Corporation early adopted the accounting standard and recognized a $1 million reduction in income taxes for the excess tax benefits on stock-based compensation. The remaining provisions of this accounting standard did not have a material impact.
ASU 2016-07 Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting	The FASB issued an amendment to eliminate the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an investor must adjust the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. Therefore, upon qualifying for the equity method of accounting, no retroactive adjustment of the investment is required. The amendments require that an entity that has an available-for-sale equity security that becomes qualified for the equity method of accounting recognize through earnings the unrealized holding gain or loss in accumulated other comprehensive income at the date the investment becomes qualified for use of the equity method. Entities should apply the amendment prospectively to increases in the level of ownership interest or degree of influence that result in the adoption of the equity method.	1st Quarter 2017	No material impact on results of operations, financial position, or liquidity.