v3.26.1
Risk management - Sensitivity analysis (Details) - EUR (€)
€ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
NETHERLANDS    
Market Risk [Line Items]    
Reportable ECL € 410 € 389
NETHERLANDS | Upside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 297 € 288
Probability weighting 20.00% 20.00%
NETHERLANDS | Upside scenario | Real GDP    
Market Risk [Line Items]    
2026 1.50% 2.60%
2027 2.90% 2.90%
2028 2.50% 2.30%
NETHERLANDS | Upside scenario | Unemployment    
Market Risk [Line Items]    
2026 3.80% 3.50%
2027 3.60% 3.20%
2028 3.50% 3.20%
NETHERLANDS | Upside scenario | HPI    
Market Risk [Line Items]    
2026 3.80% 8.20%
2027 8.40% 8.50%
2028 7.20% 7.00%
NETHERLANDS | Baseline scenario    
Market Risk [Line Items]    
Un-weighted ECL € 381 € 364
Probability weighting 60.00% 60.00%
NETHERLANDS | Baseline scenario | Real GDP    
Market Risk [Line Items]    
2026 1.00% 1.10%
2027 1.20% 1.40%
2028 1.50% 1.50%
NETHERLANDS | Baseline scenario | Unemployment    
Market Risk [Line Items]    
2026 4.20% 4.00%
2027 4.30% 3.90%
2028 4.40% 4.10%
NETHERLANDS | Baseline scenario | HPI    
Market Risk [Line Items]    
2026 2.70% 4.40%
2027 2.60% 3.00%
2028 2.70% 2.90%
NETHERLANDS | Downside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 608 € 566
Probability weighting 20.00% 20.00%
NETHERLANDS | Downside scenario | Real GDP    
Market Risk [Line Items]    
2026 0.20% (1.20%)
2027 (1.80%) (0.90%)
2028 (0.30%) 0.20%
NETHERLANDS | Downside scenario | Unemployment    
Market Risk [Line Items]    
2026 4.90% 5.50%
2027 6.30% 6.50%
2028 7.20% 7.40%
NETHERLANDS | Downside scenario | HPI    
Market Risk [Line Items]    
2026 1.20% (0.80%)
2027 (5.20%) (5.10%)
2028 (4.80%) (5.10%)
GERMANY    
Market Risk [Line Items]    
Reportable ECL € 589 € 633
GERMANY | Upside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 541 € 584
Probability weighting 20.00% 20.00%
GERMANY | Upside scenario | Real GDP    
Market Risk [Line Items]    
2026 1.30% 2.80%
2027 3.20% 3.00%
2028 2.20% 1.80%
GERMANY | Upside scenario | Unemployment    
Market Risk [Line Items]    
2026 3.30% 3.00%
2027 2.80% 2.40%
2028 2.30% 2.20%
GERMANY | Upside scenario | HPI    
Market Risk [Line Items]    
2026 2.80% 8.20%
2027 9.10% 9.80%
2028 10.00% 9.40%
GERMANY | Baseline scenario    
Market Risk [Line Items]    
Un-weighted ECL € 582 € 623
Probability weighting 60.00% 60.00%
GERMANY | Baseline scenario | Real GDP    
Market Risk [Line Items]    
2026 0.70% 1.10%
2027 1.20% 1.50%
2028 1.20% 1.30%
GERMANY | Baseline scenario | Unemployment    
Market Risk [Line Items]    
2026 3.80% 3.50%
2027 3.60% 3.20%
2028 3.40% 3.10%
GERMANY | Baseline scenario | HPI    
Market Risk [Line Items]    
2026 1.60% 5.00%
2027 4.90% 6.20%
2028 6.40% 6.30%
GERMANY | Downside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 660 € 713
Probability weighting 20.00% 20.00%
GERMANY | Downside scenario | Real GDP    
Market Risk [Line Items]    
2026 (0.20%) (1.70%)
2027 (2.20%) (1.10%)
2028 (0.50%) 0.40%
GERMANY | Downside scenario | Unemployment    
Market Risk [Line Items]    
2026 4.20% 4.70%
2027 5.30% 5.30%
2028 5.50% 5.60%
GERMANY | Downside scenario | HPI    
Market Risk [Line Items]    
2026 0.30% 0.90%
2027 (0.50%) 0.40%
2028 1.80% 2.70%
BELGIUM    
Market Risk [Line Items]    
Reportable ECL € 604 € 596
BELGIUM | Upside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 551 € 544
Probability weighting 20.00% 20.00%
BELGIUM | Upside scenario | Real GDP    
Market Risk [Line Items]    
2026 1.30% 2.70%
2027 2.60% 2.30%
2028 2.10% 1.90%
BELGIUM | Upside scenario | Unemployment    
Market Risk [Line Items]    
2026 5.60% 5.10%
2027 5.10% 4.60%
2028 4.90% 4.50%
BELGIUM | Upside scenario | HPI    
Market Risk [Line Items]    
2026 4.80% 5.20%
2027 5.00% 4.90%
2028 4.90% 5.40%
BELGIUM | Baseline scenario    
Market Risk [Line Items]    
Un-weighted ECL € 593 € 585
Probability weighting 60.00% 60.00%
BELGIUM | Baseline scenario | Real GDP    
Market Risk [Line Items]    
2026 0.70% 1.10%
2027 1.10% 1.40%
2028 1.60% 1.60%
BELGIUM | Baseline scenario | Unemployment    
Market Risk [Line Items]    
2026 6.30% 5.90%
2027 6.30% 5.60%
2028 6.00% 5.50%
BELGIUM | Baseline scenario | HPI    
Market Risk [Line Items]    
2026 4.20% 3.70%
2027 3.80% 4.20%
2028 4.20% 4.40%
BELGIUM | Downside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 692 € 682
Probability weighting 20.00% 20.00%
BELGIUM | Downside scenario | Real GDP    
Market Risk [Line Items]    
2026 (0.20%) (1.50%)
2027 (1.60%) 0.10%
2028 1.20% 1.40%
BELGIUM | Downside scenario | Unemployment    
Market Risk [Line Items]    
2026 6.90% 7.00%
2027 7.70% 7.70%
2028 8.20% 7.90%
BELGIUM | Downside scenario | HPI    
Market Risk [Line Items]    
2026 3.50% 1.80%
2027 1.70% 2.60%
2028 2.70% 2.60%
UNITED STATES    
Market Risk [Line Items]    
Reportable ECL € 98 € 105
UNITED STATES | Upside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 67 € 64
Probability weighting 20.00% 20.00%
UNITED STATES | Upside scenario | Real GDP    
Market Risk [Line Items]    
2026 2.50% 3.20%
2027 3.20% 2.90%
2028 2.90% 2.70%
UNITED STATES | Upside scenario | Unemployment    
Market Risk [Line Items]    
2026 3.90% 3.20%
2027 2.90% 2.50%
2028 2.60% 2.60%
UNITED STATES | Upside scenario | HPI    
Market Risk [Line Items]    
2026 3.30% 4.80%
2027 7.90% 9.40%
2028 11.20% 10.90%
UNITED STATES | Baseline scenario    
Market Risk [Line Items]    
Un-weighted ECL € 89 € 92
Probability weighting 60.00% 60.00%
UNITED STATES | Baseline scenario | Real GDP    
Market Risk [Line Items]    
2026 2.10% 2.00%
2027 2.00% 2.00%
2028 2.10% 2.00%
UNITED STATES | Baseline scenario | Unemployment    
Market Risk [Line Items]    
2026 4.60% 4.30%
2027 4.40% 4.10%
2028 4.20% 4.10%
UNITED STATES | Baseline scenario | HPI    
Market Risk [Line Items]    
2026 2.30% 1.40%
2027 2.60% 2.70%
2028 3.50% 3.60%
UNITED STATES | Downside scenario    
Market Risk [Line Items]    
Un-weighted ECL € 159 € 184
Probability weighting 20.00% 20.00%
UNITED STATES | Downside scenario | Real GDP    
Market Risk [Line Items]    
2026 1.20% (0.40%)
2027 (1.00%) (0.10%)
2028 0.70% 0.80%
UNITED STATES | Downside scenario | Unemployment    
Market Risk [Line Items]    
2026 6.20% 6.70%
2027 7.10% 7.20%
2028 7.50% 7.50%
UNITED STATES | Downside scenario | HPI    
Market Risk [Line Items]    
2026 0.40% (5.10%)
2027 (7.60%) (7.90%)
2028 (6.10%) (5.50%)