Statement Of Comprehensive Income [Abstract]
| Concept |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2023-04-01 to 2024-03-31 |
2022-04-01 to 2023-03-31 |
2022-04-01 to 2023-03-31 |
2022-04-01 to 2023-03-31 |
2022-04-01 to 2023-03-31 |
2022-04-01 to 2023-03-31 |
2022-04-01 to 2023-03-31 |
2022-04-01 to 2023-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||
| Profit (loss) | — | — | — |
341,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
622,000,000
GBP
|
| Other comprehensive income [abstract] | ||||||||||||||
| Components of other comprehensive income that will not be reclassified to profit or loss, before tax [abstract] | ||||||||||||||
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans | — | — | — |
5,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
12,000,000
GBP
|
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||||||
| Income tax relating to remeasurements of defined benefit plans included in other comprehensive income | — | — | — |
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
3,000,000
GBP
|
| Other comprehensive income | — | — | — |
2,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
10,000,000
GBP
|
| Comprehensive income |
22,000,000
GBP
|
–
GBP
|
321,000,000
GBP
|
343,000,000
GBP
|
–
GBP
|
–
GBP
|
321,000,000
GBP
|
629,000,000
GBP
|
629,000,000
GBP
|
–
GBP
|
3,000,000
GBP
|
–
GBP
|
–
GBP
|
632,000,000
GBP
|
| Comprehensive income attributable to [abstract] | ||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — |
321,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
629,000,000
GBP
|
| Comprehensive income, attributable to non-controlling interests | — | — | — |
22,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
3,000,000
GBP
|