Loans and Related Allowance for Credit Losses (Rollforward of Allowance for Credit Losses of Loans and Leases) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jun. 01, 2021	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		$ 4,714	$ 3,944	$ 5,361	$ 2,742
Acquisition PCD reserves		1,115		1,115
Charge-offs		(428)	(314)	(671)	(618)
Recoveries		122	78	219	170
Net (charge-offs)		(306)	(236)	(452)	(448)
Provision for (recapture of) credit losses		206	2,220	(296)	3,172
Other		1		2	(1)
Ending balance		5,730	5,928	5,730	5,928
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance		507	450	584	318
Acquisition PCD reserves		46		46
Provision for (recapture of) credit losses		92	212	15	165
Ending balance		645	662	645	662
Allowance for credit loss		6,375	6,590	6,375	6,590
Allowances for investment securities and other financial assets		138	51	138	51
BBVA USA Bancshares, Inc.
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Acquisition PCD reserves	$ 1,161
Net (charge-offs)		(248)		(248)
Total commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		3,083	1,979	3,337	1,812
Acquisition PCD reserves		828		828
Charge-offs		(274)	(122)	(343)	(205)
Recoveries		34	15	52	39
Net (charge-offs)		(240)	(107)	(291)	(166)
Provision for (recapture of) credit losses		140	1,508	(64)	2,039
Other		1		2	(1)
Ending balance		3,812	3,380	3,812	3,380
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance		403	344	485	316
Acquisition PCD reserves		43		43
Provision for (recapture of) credit losses		87	204	5	179
Ending balance		533	548	533	548
Allowance for credit loss		4,345	3,928	4,345	3,928
Total consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		1,631	1,965	2,024	930
Acquisition PCD reserves		287		287
Charge-offs		(154)	(192)	(328)	(413)
Recoveries		88	63	167	131
Net (charge-offs)		(66)	(129)	(161)	(282)
Provision for (recapture of) credit losses		66	712	(232)	1,133
Ending balance		1,918	2,548	1,918	2,548
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance		104	106	99	2
Acquisition PCD reserves		3		3
Provision for (recapture of) credit losses		5	8	10	(14)
Ending balance		112	114	112	114
Allowance for credit loss		2,030	2,662	2,030	2,662
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance					463
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance					179
Cumulative Effect, Period of Adoption, Adjustment | Total commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance					(304)
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance					53
Cumulative Effect, Period of Adoption, Adjustment | Total consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance					767
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance					126
Cumulative Effect, Period of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		4,714	3,944	5,361	3,205
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance		507	450	584	497
Cumulative Effect, Period of Adoption, Adjusted Balance | Total commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		3,083	1,979	3,337	1,508
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance		403	344	485	369
Cumulative Effect, Period of Adoption, Adjusted Balance | Total consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance		1,631	1,965	2,024	1,697
Off-Balance Sheet, Credit Loss, Liability [Roll Forward]
Beginning balance		$ 104	$ 106	$ 99	$ 128