Note 23 - Assets and Liabilities under reinsurance and insurance contracts. Mathematical Reserves (Details) - EUR (€)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Matematical Reserves Line Items
INSURANCE OR REINSURANCE ASSETS		€ 341,000,000	€ 366,000,000	€ 421,000,000
Spain [Member] | Individual Insurance [Member]
Matematical Reserves Line Items
Mortality Table	[1]	GRMF 80-2, GKMF 80/95. PASEM, PERMF 2000
Average Technical Interest Type	[1]	0.25% -2.91%
Spain [Member] | Savings Insurance [Member]
Matematical Reserves Line Items
Mortality Table	[2]	PERMF 2000
Average Technical Interest Type	[2]	Depending on the related portfolio
Mexico [Member] | Individual Insurance [Member]
Matematical Reserves Line Items
Mortality Table	[1]	Tables of the Comisión Nacional de Seguros y Fianzas 2000-individual
Average Technical Interest Type	[1]	2.50%
Mexico [Member] | Savings Insurance [Member]
Matematical Reserves Line Items
Mortality Table	[2]	Tables of the Comisión Nacional de Seguros y Fianzas 2000-grupo
Average Technical Interest Type	[2]	5.50%

[1] (1) Provides coverage in the case of one or more of the following events: death and disability.

[2] (2) Insurance policies purchased by companies (other than Group BBVA entities) on behalf of their employees.