Retirement benefit obligations - Schedule of Net Retirement Benefits Amounts Recognized in Balance Sheet (Details) - GBP (£) £ in Millions |
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|---|---|---|---|
| RETIREMENT BENEFIT OBLIGATIONS (Details) - Schedule of Retirement Benefits Amounts Recognized in Balance Sheet [Line Items] | |||
| Defined benefit asset | £ 2,575 | £ 2,906 | |
| Defined benefit pension schemes | |||
| RETIREMENT BENEFIT OBLIGATIONS (Details) - Schedule of Retirement Benefits Amounts Recognized in Balance Sheet [Line Items] | |||
| Defined benefit asset | 2,612 | 2,945 | £ 3,532 |
| Present value of funded obligations | |||
| RETIREMENT BENEFIT OBLIGATIONS (Details) - Schedule of Retirement Benefits Amounts Recognized in Balance Sheet [Line Items] | |||
| Defined benefit asset | (26,571) | (27,118) | (30,201) |
| Fair value of scheme assets | |||
| RETIREMENT BENEFIT OBLIGATIONS (Details) - Schedule of Retirement Benefits Amounts Recognized in Balance Sheet [Line Items] | |||
| Defined benefit asset | £ 29,183 | £ 30,063 | £ 33,733 |