Pensions and other post-retirement benefit obligations - Narrative (Details) £ in Millions |
Sep. 30, 2026
GBP (£)
plan
|
Mar. 31, 2026
GBP (£)
plan
|
Sep. 30, 2025
GBP (£)
|
Mar. 31, 2025
GBP (£)
|
|---|---|---|---|---|
| Disclosure of defined benefit plans [line items] | ||||
| Irrecoverable surplus | £ 492 | £ 244 | ||
| Number of other post-employment benefit plan | plan | 3 | 1 | ||
| UK | ||||
| Disclosure of defined benefit plans [line items] | ||||
| Funding surplus/(deficit) | £ 1,201 | £ 1,122 | ||
| US | ||||
| Disclosure of defined benefit plans [line items] | ||||
| Funding surplus/(deficit) | 1,416 | 1,385 | ||
| US | Post-employment medical defined benefit plans | ||||
| Disclosure of defined benefit plans [line items] | ||||
| Irrecoverable surplus | £ 492 | £ 244 | £ 221 | £ 77 |