Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net interest income (expense)	$ 589,455	$ 683,089
Provision for credit losses	356,991	182,292
Noninterest income	334,242	257,760
Noninterest expense	2,809,060	581,973
Net (loss) income before income tax expense	(2,242,354)	176,584
Income tax expense (benefit)	(5,069)	35,603
Net (loss) income	(2,237,285)	140,981
Less: net income attributable to noncontrolling interests	501	556
Net (loss) income attributable to BBVA USA Bancshares, Inc.	(2,237,786)	140,425
Average assets	96,356,113	92,985,876
Operating Segments | Commercial Banking and Wealth
Segment Reporting Information [Line Items]
Net interest income (expense)	266,837	315,332
Provision for credit losses	42,184	57,440
Noninterest income	68,535	57,375
Noninterest expense	174,583	167,968
Net (loss) income before income tax expense	118,605	147,299
Income tax expense (benefit)	24,685	30,933
Net (loss) income	93,920	116,366
Less: net income attributable to noncontrolling interests	116	96
Net (loss) income attributable to BBVA USA Bancshares, Inc.	93,804	116,270
Average assets	41,177,867	40,393,329
Operating Segments | Retail Banking
Segment Reporting Information [Line Items]
Net interest income (expense)	295,009	349,377
Provision for credit losses	66,729	103,405
Noninterest income	130,704	111,919
Noninterest expense	305,258	297,923
Net (loss) income before income tax expense	53,726	59,968
Income tax expense (benefit)	11,494	12,593
Net (loss) income	42,232	47,375
Less: net income attributable to noncontrolling interests	0	0
Net (loss) income attributable to BBVA USA Bancshares, Inc.	42,232	47,375
Average assets	18,697,233	18,932,712
Operating Segments | Corporate and Investment Banking
Segment Reporting Information [Line Items]
Net interest income (expense)	30,779	33,818
Provision for credit losses	92,970	25,930
Noninterest income	40,135	36,517
Noninterest expense	61,395	39,879
Net (loss) income before income tax expense	(83,451)	4,526
Income tax expense (benefit)	(17,525)	950
Net (loss) income	(65,926)	3,576
Less: net income attributable to noncontrolling interests	0	0
Net (loss) income attributable to BBVA USA Bancshares, Inc.	(65,926)	3,576
Average assets	8,282,036	8,214,217
Operating Segments | Treasury
Segment Reporting Information [Line Items]
Net interest income (expense)	(36,427)	(20,024)
Provision for credit losses	(237)	373
Noninterest income	26,202	12,486
Noninterest expense	4,046	5,589
Net (loss) income before income tax expense	(14,034)	(13,500)
Income tax expense (benefit)	(2,947)	(2,835)
Net (loss) income	(11,087)	(10,665)
Less: net income attributable to noncontrolling interests	396	405
Net (loss) income attributable to BBVA USA Bancshares, Inc.	(11,483)	(11,070)
Average assets	20,254,208	17,214,202
Corporate Support and Other
Segment Reporting Information [Line Items]
Net interest income (expense)	33,257	4,586
Provision for credit losses	155,345	(4,856)
Noninterest income	68,666	39,463
Noninterest expense	2,263,778	70,614
Net (loss) income before income tax expense	(2,317,200)	(21,709)
Income tax expense (benefit)	(20,776)	(6,038)
Net (loss) income	(2,296,424)	(15,671)
Less: net income attributable to noncontrolling interests	(11)	55
Net (loss) income attributable to BBVA USA Bancshares, Inc.	(2,296,413)	(15,726)
Average assets	$ 7,944,769	$ 8,231,416