Commitments, Contingencies and Guarantees - Narrative (Details)	1 Months Ended				3 Months Ended		12 Months Ended
	Jan. 31, 2016 security_offering	Mar. 31, 2014 USD ($)	Jun. 30, 2013 patent	May. 31, 2013 USD ($)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Loss contingency accrual					$ 30,000,000
FDIC indemnification expense					4,710,000	$ 28,789,000
Financial Standby Letter of Credit
Loss Contingencies [Line Items]
Letters of credit, deferred fees					6,400,000		$ 6,000,000
Maximum potential amount of future undiscounted payments Company could be required to make on outstanding standby letters of credit					$ 1,500,000,000
Financial Standby Letter of Credit | Minimum
Loss Contingencies [Line Items]
Standby and commercial letters of credit expiration term					1 year
Financial Standby Letter of Credit | Maximum
Loss Contingencies [Line Items]
Standby and commercial letters of credit expiration term					4 years
Potential Recourse Related To FNMA Securitizations
Loss Contingencies [Line Items]
Potential recourse					$ 19,000,000		19,000,000
FDIC Loss Sharing Agreement
Loss Contingencies [Line Items]
Covered loans					$ 9,700,000,000
Loan losses reimbursable by FDIC, percentage of loss reimbursable					80.00%
FDIC indemnification asset, threshold loss amount					$ 2,300,000,000.0
FDIC indemnification asset, percentage of incurred losses above threshold, amount reimbursed					95.00%
FDIC loss sharing agreement, term					10 years
Loss sharing agreement, percentage owed by company to FDIC if terms are met					60.00%
Loss sharing agreement, threshold amount					$ 457,000,000
Loss sharing agreement, percentage of net amount paid to company, subject to repayment to FDIC					25.00%
Loss sharing agreement, administration costs for loans, percentage subject to repayment to FDIC					20.00%
Loss sharing agreement, average administration cost percentage					2.00%
Loss sharing agreement, amount owed to FDIC					$ 146,000,000		145,000,000
FDIC Loss Sharing Agreement | Commercial Loan
Loss Contingencies [Line Items]
FDIC loss sharing agreement, term					5 years
FDIC Loss Sharing Agreement | Single Family Residential Loan
Loss Contingencies [Line Items]
FDIC loss sharing agreement, term					10 years
Accrued Expenses and Other Liabilities
Loss Contingencies [Line Items]
FDIC indemnification expense					$ 136,000,000		131,000,000
Accrued Expenses and Other Liabilities | Financial Standby Letter of Credit
Loss Contingencies [Line Items]
Loss contingency accrual					111,000,000		85,000,000
Accrued Expenses and Other Liabilities | Potential Recourse Related To FNMA Securitizations
Loss Contingencies [Line Items]
Loss contingency accrual					658,000		869,000
Accrued Expenses and Other Liabilities | Standard Representations And Warranties Related To Loan Sales To Government-Sponsored Agencies
Loss Contingencies [Line Items]
Loss contingency accrual					$ 2,000,000		$ 2,000,000
Pending Litigation | Morris Cerullo World Evangelism v. BBVA Compass and Jack Wilkinson
Loss Contingencies [Line Items]
Damages sought				$ 5,200,000
Pending Litigation | Morris Cerullo World Evangelism v. BBVA Compass and Jack Wilkinson | Financial Standby Letter of Credit
Loss Contingencies [Line Items]
Line of credit				$ 5,200,000
Pending Litigation | Intellectual Ventures II, LLC vs BBVA Compass Bancshares, Inc
Loss Contingencies [Line Items]
Loss contingency, patents allegedly infringed | patent			5
Pending Litigation | Jack Demetree Vs. BBVA Compass
Loss Contingencies [Line Items]
Damages sought		$ 16,400,000
Pending Litigation | In re Plains All American Pipeline, L.P. Securities Litigation | BSI
Loss Contingencies [Line Items]
Loss contingency, number of security offers challenged | security_offering	8