Fair value of financial instruments - Disclosure of fair value adjustments (Details) - Level 3 - GBP (£) £ in Millions |
Dec. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Exit price adjustments derived from market bid-offer spreads | ||
| Disclosure of detailed information about financial instruments [line items] | ||
| Fair value adjustments | £ (618) | £ (529) |
| Uncollateralised derivative funding | ||
| Disclosure of detailed information about financial instruments [line items] | ||
| Fair value adjustments | 62 | 19 |
| Derivative credit valuation adjustments | ||
| Disclosure of detailed information about financial instruments [line items] | ||
| Fair value adjustments | (155) | (184) |
| Derivative debit valuation adjustments | ||
| Disclosure of detailed information about financial instruments [line items] | ||
| Fair value adjustments | £ 119 | £ 108 |