Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 166,241	$ 182,945	$ (2,195,481)	$ 484,112
Other comprehensive income, net of tax:
Net unrealized (losses) gains arising during period from debt securities available for sale	(6,311)	32,464	125,103	169,868
Less: reclassification adjustment for net gains on sale of debt securities available for sale in net income	0	16,023	17,220	22,857
Net change in net unrealized holding (losses) gains on debt securities available for sale	(6,311)	16,441	107,883	147,011
Change in unamortized net holding gains on debt securities held to maturity	1,644	2,223	4,924	5,905
Less: non-credit related impairment on debt securities held to maturity	0	0	0	82
Change in unamortized non-credit related impairment on debt securities held to maturity	102	175	341	675
Net change in unamortized holding gains on debt securities held to maturity	1,746	2,398	5,265	6,498
Unrealized holding (losses) gains arising during period from cash flow hedge instruments	(34,226)	33,662	251,544	131,665
Change in defined benefit plans	0	0	1,754	3,119
Other comprehensive (loss) income, net of tax	(38,791)	52,501	366,446	288,293
Comprehensive income (loss)	127,450	235,446	(1,829,035)	772,405
Less: comprehensive income attributable to noncontrolling interests	401	514	1,374	1,669
Comprehensive income (loss) attributable to BBVA USA Bancshares, Inc.	$ 127,049	$ 234,932	$ (1,830,409)	$ 770,736