Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 622,605	$ 551,433
Provision (credit) for loan losses	57,029	80,139
Noninterest income	257,825	244,687
Noninterest expense	562,913	549,312
Net income before income tax expense	260,488	166,669
Income tax expense (benefit)	51,798	45,846
Net income	208,690	120,823
Less: net income attributable to noncontrolling interests	461	443
Net income attributable to BBVA Compass Bancshares, Inc.	208,229	120,380
Average assets	87,770,909	87,676,882
Commercial Banking and Wealth
Segment Reporting Information [Line Items]
Noninterest income	61,236	49,885
Retail Banking
Segment Reporting Information [Line Items]
Noninterest income	108,752	106,569
Corporate and Investment Banking
Segment Reporting Information [Line Items]
Noninterest income	41,792	46,684
Operating Segments | Commercial Banking and Wealth
Segment Reporting Information [Line Items]
Net interest income (expense)	301,618	270,975
Provision (credit) for loan losses	20,407	22,191
Noninterest income	61,236	49,885
Noninterest expense	176,749	158,639
Net income before income tax expense	165,698	140,030
Income tax expense (benefit)	34,797	49,010
Net income	130,901	91,020
Less: net income attributable to noncontrolling interests	35	23
Net income attributable to BBVA Compass Bancshares, Inc.	130,866	90,997
Average assets	37,667,960	35,814,212
Operating Segments | Retail Banking
Segment Reporting Information [Line Items]
Net interest income (expense)	259,829	223,712
Provision (credit) for loan losses	29,057	37,264
Noninterest income	108,752	106,569
Noninterest expense	286,826	292,700
Net income before income tax expense	52,698	317
Income tax expense (benefit)	11,066	111
Net income	41,632	206
Less: net income attributable to noncontrolling interests	0	0
Net income attributable to BBVA Compass Bancshares, Inc.	41,632	206
Average assets	18,258,376	17,998,731
Operating Segments | Corporate and Investment Banking
Segment Reporting Information [Line Items]
Net interest income (expense)	42,587	35,295
Provision (credit) for loan losses	(18,209)	5,720
Noninterest income	41,792	46,684
Noninterest expense	39,610	38,760
Net income before income tax expense	62,978	37,499
Income tax expense (benefit)	13,226	13,125
Net income	49,752	24,374
Less: net income attributable to noncontrolling interests	0	0
Net income attributable to BBVA Compass Bancshares, Inc.	49,752	24,374
Average assets	8,280,917	11,010,571
Operating Segments | Treasury
Segment Reporting Information [Line Items]
Net interest income (expense)	(4,067)	23,260
Provision (credit) for loan losses	(121)	0
Noninterest income	6,725	6,352
Noninterest expense	5,589	6,308
Net income before income tax expense	(2,810)	23,304
Income tax expense (benefit)	(590)	8,156
Net income	(2,220)	15,148
Less: net income attributable to noncontrolling interests	409	416
Net income attributable to BBVA Compass Bancshares, Inc.	(2,629)	14,732
Average assets	15,898,805	15,180,526
Corporate Support and Other
Segment Reporting Information [Line Items]
Net interest income (expense)	22,638	(1,809)
Provision (credit) for loan losses	25,895	14,964
Noninterest income	39,320	35,197
Noninterest expense	54,139	52,905
Net income before income tax expense	(18,076)	(34,481)
Income tax expense (benefit)	(6,701)	(24,556)
Net income	(11,375)	(9,925)
Less: net income attributable to noncontrolling interests	17	4
Net income attributable to BBVA Compass Bancshares, Inc.	(11,392)	(9,929)
Average assets	$ 7,664,851	$ 7,672,842