Basis of Presentation	3 Months Ended
Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation General The accounting and reporting policies of the Company and the methods of applying those policies that materially affect the consolidated financial statements conform with U.S. GAAP and with general financial services industry practices. The accompanying unaudited consolidated financial statements include the accounts of BBVA Compass Bancshares, Inc. and its subsidiaries and have been prepared in conformity with U.S. GAAP for interim financial information and in accordance with the instructions to Quarterly Report on Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission. In the opinion of management, all adjustments, consisting of normal and recurring items, necessary for the fair presentation of the condensed consolidated financial statements have been included. Operating results for the three months ended March 31, 2017, are not necessarily indicative of the results that may be expected for the year ended December 31, 2017. These interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. The Company has evaluated subsequent events for potential recognition and disclosure through the filing date of this Quarterly Report on Form 10-Q to determine if either recognition or disclosure of significant events or transactions is required. Use of Estimates in the Preparation of Consolidated Financial Statements The preparation of consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period, the most significant of which relate to the allowance for loan losses, goodwill impairment, fair value measurements and income taxes. Actual results could differ from those estimates. Recently Adopted Accounting Standards Stock Compensation In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting. The FASB issued this ASU to improve the accounting for share-based payment transactions as part of its simplification initiative. The areas for simplification in this ASU involve 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. The amendments in this ASU were effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. The adoption of this standard did not have an impact on the financial condition or results of operations of the Company. Recently Issued Accounting Standards Not Yet Adopted Revenue from Contracts with Customers In May 2014, the FASB released ASU 2014-09, Revenue from Contracts with Customers. The core principle of this codified guidance requires an entity to recognize revenue upon 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 amendments in this ASU were originally effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. Subsequently, the FASB issued a one-year deferral for implementation, which results in the new guidance being effective for annual and interim reporting periods beginning after December 15, 2017. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company and its selection of transition method. Because the guidance does not apply to revenue associated with financial instruments, including loans and securities accounted for under other U.S. GAAP, the Company does not expect the new revenue recognition guidance to have a material impact on the elements of its statement of income most closely associated with financial instruments, including securities gains, interest income and interest expense. The Company plans to adopt this standard utilizing a modified retrospective transition method in the first quarter of 2018. Recognition and Measurement of Financial Assets and Liabilities In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Liabilities. The amendments in this ASU revise an entity's accounting related to the classification and measurement of investments in equity securities and the presentation of certain fair value changes for financial liabilities measured at fair value. The ASU also amends certain disclosure requirements associated with the fair value of financial instruments. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted for the presentation of certain fair value changes for financial liabilities measured at fair value. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company. Leases In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The FASB issued this ASU to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet by lessees for those leases classified as operating leases under current U.S. GAAP and disclosing key information about leasing arrangements. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2018. Early application of this ASU is permitted for all entities. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company. Credit Losses In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses, which introduces new guidance for the accounting for credit losses on instruments within its scope. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. It also modifies the impairment model for AFS debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2019. Early application of this ASU is permitted. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company. Statement of Cash Flows In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments, which provides guidance on eight specific cash flow issues with the objective of reducing the existing diversity in practice. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early application of this ASU is permitted. The Company is currently assessing the impact that the adoption of this standard will have on the Statements of Cash Flows of the Company. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows - Restricted Cash. The amendments in this ASU require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early application of this ASU is permitted. The Company is currently assessing the impact that the adoption of this standard will have on the Statement of Cash Flows of the Company. Goodwill In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which simplifies the manner in which an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Under the amendments in this ASU, an entity should (1) perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and (2) recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the understanding that the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, ASU No. 2017-04 removes the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails such qualitative test, to perform Step 2 of the goodwill impairment test. This ASU is effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The ASU should be applied using a prospective method. The Company is currently assessing this pronouncement and the impact of adoption. Retirement Benefits In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The amendments in this ASU require that an employer disaggregate the service cost component from the other components of net benefit cost. The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow only the service cost component of net benefit cost to be eligible for capitalization. This ASU is effective for fiscal years beginning after December 15, 2017, and for interim periods within those fiscal years. Early adoption is permitted. The ASU should be applied retrospectively for the presentation of the service cost component and the other components of net benefit cost in the income statement and prospectively, on and after the effective date, for the capitalization of the service cost component of net benefit cost. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company. Premium Amortization on Purchased Callable Debt Securities In March 2017, the FASB issued ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities. The amendments in this ASU reduce the amortization period for certain callable debt securities carried at a premium and require the premium to be amortized over a period not to exceed the earliest call date. These amendments do not apply to securities carried at a discount. This ASU is effective for fiscal years beginning after December 15, 2018, and for interim periods within those fiscal years. Early adoption is permitted. The ASU should be applied using a modified retrospective method. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company.

Basis of Presentation

General

The accounting and reporting policies of the Company and the methods of applying those policies that materially affect the consolidated financial statements conform with U.S. GAAP and with general financial services industry practices. The accompanying unaudited consolidated financial statements include the accounts of BBVA Compass Bancshares, Inc. and its subsidiaries and have been prepared in conformity with U.S. GAAP for interim financial information and in accordance with the instructions to Quarterly Report on Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission. In the opinion of management, all adjustments, consisting of normal and recurring items, necessary for the fair presentation of the condensed consolidated financial statements have been included. Operating results for the three months ended March 31, 2017, are not necessarily indicative of the results that may be expected for the year ended December 31, 2017. These interim financial statements should be read in conjunction with the consolidated financial statements and notes thereto in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.

The Company has evaluated subsequent events for potential recognition and disclosure through the filing date of this Quarterly Report on Form 10-Q to determine if either recognition or disclosure of significant events or transactions is required.

Use of Estimates in the Preparation of Consolidated Financial Statements

The preparation of consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period, the most significant of which relate to the allowance for loan losses, goodwill impairment, fair value measurements and income taxes. Actual results could differ from those estimates.

Recently Adopted Accounting Standards

Stock Compensation

In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting. The FASB issued this ASU to improve the accounting for share-based payment transactions as part of its simplification initiative. The areas for simplification in this ASU involve 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. The amendments in this ASU were effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. The adoption of this standard did not have an impact on the financial condition or results of operations of the Company.

Recently Issued Accounting Standards Not Yet Adopted

Revenue from Contracts with Customers

In May 2014, the FASB released ASU 2014-09, Revenue from Contracts with Customers. The core principle of this codified guidance requires an entity to recognize revenue upon 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 amendments in this ASU were originally effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. Subsequently, the FASB issued a one-year deferral for implementation, which results in the new guidance being effective for annual and interim reporting periods beginning after December 15, 2017. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company and its selection of transition method. Because the guidance does not apply to revenue associated with financial instruments, including loans and securities accounted for under other U.S. GAAP, the Company does not expect the new revenue recognition guidance to have a material impact on the elements of its statement of income most closely associated with financial instruments, including securities gains, interest income and interest expense. The Company plans to adopt this standard utilizing a modified retrospective transition method in the first quarter of 2018.

Recognition and Measurement of Financial Assets and Liabilities

In January 2016, the FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Liabilities. The amendments in this ASU revise an entity's accounting related to the classification and measurement of investments in equity securities and the presentation of certain fair value changes for financial liabilities measured at fair value. The ASU also amends certain disclosure requirements associated with the fair value of financial instruments. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted for the presentation of certain fair value changes for financial liabilities measured at fair value. The adoption of this standard is not expected to have a material impact on the financial condition or results of operations of the Company.

Leases

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The FASB issued this ASU to increase transparency and comparability among organizations by recognizing lease assets and lease liabilities on the balance sheet by lessees for those leases classified as operating leases under current U.S. GAAP and disclosing key information about leasing arrangements. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2018. Early application of this ASU is permitted for all entities. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company.

Credit Losses

In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses, which introduces new guidance for the accounting for credit losses on instruments within its scope. The new guidance introduces an approach based on expected losses to estimate credit losses on certain types of financial instruments. It also modifies the impairment model for AFS debt securities and provides for a simplified accounting model for purchased financial assets with credit deterioration since their origination. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2019. Early application of this ASU is permitted. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company.

Statement of Cash Flows

In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments, which provides guidance on eight specific cash flow issues with the objective of reducing the existing diversity in practice. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early application of this ASU is permitted. The Company is currently assessing the impact that the adoption of this standard will have on the Statements of Cash Flows of the Company.

In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows - Restricted Cash. The amendments in this ASU require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. The amendments in this ASU are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early application of this ASU is permitted. The Company is currently assessing the impact that the adoption of this standard will have on the Statement of Cash Flows of the Company.

Goodwill

In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which simplifies the manner in which an entity is required to test goodwill for impairment by eliminating Step 2 from the goodwill impairment test. Under the amendments in this ASU, an entity should (1) perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount, and (2) recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value, with the understanding that the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. Additionally, ASU No. 2017-04 removes the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails such qualitative test, to perform Step 2 of the goodwill impairment test. This ASU is effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The ASU should be applied using a prospective method. The Company is currently assessing this pronouncement and the impact of adoption.

Retirement Benefits

In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The amendments in this ASU require that an employer disaggregate the service cost component from the other components of net benefit cost. The amendments also provide explicit guidance on how to present the service cost component and the other components of net benefit cost in the income statement and allow only the service cost component of net benefit cost to be eligible for capitalization. This ASU is effective for fiscal years beginning after December 15, 2017, and for interim periods within those fiscal years. Early adoption is permitted. The ASU should be applied retrospectively for the presentation of the service cost component and the other components of net benefit cost in the income statement and prospectively, on and after the effective date, for the capitalization of the service cost component of net benefit cost. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company.

Premium Amortization on Purchased Callable Debt Securities

In March 2017, the FASB issued ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities. The amendments in this ASU reduce the amortization period for certain callable debt securities carried at a premium and require the premium to be amortized over a period not to exceed the earliest call date. These amendments do not apply to securities carried at a discount. This ASU is effective for fiscal years beginning after December 15, 2018, and for interim periods within those fiscal years. Early adoption is permitted. The ASU should be applied using a modified retrospective method. The Company is currently assessing the impact that the adoption of this standard will have on the financial condition and results of operations of the Company.