Basis of Presentation and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with GAAP requires management to make estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and revenue and expenses during the period reported. Actual results could differ from those estimates.
Subsequent Events, Policy [Policy Text Block]	Evaluation of Subsequent Events The Company evaluated subsequent events through the date that our Condensed Consolidated Financial Statements were issued. No matters were identified that required adjustment of the Condensed Consolidated Financial Statements or additional disclosure.
Reclassifications	Reclassifications Certain prior-period amounts have been reclassified in the accompanying Condensed Consolidated Financial Statements and Notes thereto in order to conform to the current period presentation.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Issued In May 2014, the FASB issued a new revenue recognition standard that will supersede current revenue recognition guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The standard will be effective for the first interim period within annual periods beginning after December 15, 2017, with early adoption permitted for annual periods beginning after December 15, 2016, and can be adopted either retrospectively to each prior reporting period presented or as a cumulative effect adjustment as of the date of adoption. We are currently in the assessment phase of implementing this standard. We have determined a substantial majority of our new accounting policies that will be effective upon adoption. We have not yet quantified and are not yet able to make a reasonable estimate of the impact of the new revenue standard on our consolidated financial statements. As we continue our analysis of the impact on our consolidated financial statements and related disclosures, we will evaluate and determine the appropriate adoption methodology for the Company. There are also certain considerations related to internal control over financial reporting that are associated with implementing the standard. We are currently evaluating our control framework and identifying any changes that may need to be made in response to the new guidance. In February 2016, the FASB issued a new leasing standard that will supersede current guidance related to accounting for leases. The guidance is intended to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. The standard will be effective for the first interim period within annual periods beginning after December 15, 2018, with early adoption permitted. The standard is required to be adopted using the modified retrospective approach. The Company is evaluating the impact that adopting this guidance will have on its consolidated financial statements and internal controls over financial reporting. In January 2017, the FASB issued an accounting standards update which clarifies the definition of a business which is used across several areas of accounting. The area expected to see the most change is the evaluation of whether a transaction should be accounted for as an acquisition (or disposal) of assets, or as a businesses combination. The new guidance clarifies that to be a business there must also be at least one substantive process, and narrows the definition of outputs by more closely aligning it with how outputs are described in the new revenue recognition standard. The accounting standard update is required to be adopted for annual periods beginning after December 15, 2017, including interim periods within that annual period. The amendment is to be applied prospectively with early adoption permitted. We do not expect the adoption of this standard to have a material effect on our financial condition, results of operations or disclosures, as the standard applies only to businesses acquired after the adoption date. In January 2017, the FASB issued an accounting standards update with new guidance intended to simplify the subsequent measurement of goodwill. The standards update eliminates the requirement for an entity to calculate the implied fair value of goodwill to measure a goodwill impairment charge. Instead, an entity will perform its annual, or interim, goodwill impairment testing by comparing the fair value of a reporting unit with its carrying amount and recording an impairment charge for the amount by which the carrying amount exceeds the fair value. The standards update is effective prospectively for annual and interim goodwill impairment testing performed in fiscal years beginning after December 15, 2019. The adoption of this standards update is not expected to impact our consolidated financial statements. In March 2017, the FASB issued an accounting standards update with new guidance on the employer's presentation of defined benefit retirement costs in the income statement. Employers will present the service cost component of net periodic benefit cost in the same income statement line item(s) as other employee compensation costs arising from services rendered during the period. Only the service cost component will be eligible for capitalization in assets. Employers will present the other components of the net periodic benefit cost separately from the line item(s) that includes the service cost and outside of any subtotal of operating income, if one is presented. These components will not be eligible for capitalization in assets. The guidance is effective for fiscal years beginning after December 15, 2017, and interim periods therein, with early adoption permitted. The adoption of this accounting standard update is not expected to have a material effect on the Company's net income, cash flows or financial condition. Adopted In March 2016, the FASB issued an accounting standards update that amended the accounting standard related to employee share-based payments. The guidance requires the recognition of the income tax effects of awards in the income statement when the awards vest or are settled, thus eliminating additional paid in capital pools. The guidance also allows for the employer to repurchase more of an employee’s shares for tax withholding purposes without triggering liability accounting. In addition, the guidance allows for a policy election to account for forfeitures as they occur rather than on an estimated basis. The adoption approach varies based on the amendment topic. As a result of the adoption, we recorded an adjustment to beginning retained earnings of approximately $39 million to recognize federal tax credit carryforwards attributable to excess tax benefits on stock compensation that had not been previously recognized to additional paid in capital. The Company also expects the new standard to have an on-going impact on the recording of excess tax benefits and deficiencies in our consolidated balance sheets and consolidated statements of income and comprehensive income. However, the magnitude of such impact is dependent upon our future grants of stock awards, our future stock price in relation to the fair value of awards on the grant date and the exercise behavior of stock option holders.