Note 13 - Sensitivity Analysis by Type Parenthetical Information (Detail: Text Values) - Valuation technique unobservable parameters (Level 3) [Member]	12 Months Ended
	Dec. 31, 2023 EUR (€)
Positive fair value movement from using reasonable possible alternatives [Member]
Sensitivity Analysis by Type of Instrument [Line Items]
Changes in sensitive amounts during the year	€ 169,000,000
Changes in sensitive amounts during the year in percent	0.09
Negative fair value movement from using reasonable possible alternatives [Member]
Sensitivity Analysis by Type of Instrument [Line Items]
Changes in sensitive amounts during the year	€ 79,000,000
Changes in sensitive amounts during the year in percent	0.06