Statement Of Comprehensive Income [Abstract]
| Concept |
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 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||
| Profit (loss) | — |
4,064,000,000
GBP
|
509,000,000
GBP
|
4,573,000,000
GBP
|
3,547,000,000
GBP
|
— |
466,000,000
GBP
|
4,013,000,000
GBP
|
| Other comprehensive income [abstract] | ||||||||
| Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract] | ||||||||
| Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans | — |
8,000,000
GBP
|
— |
8,000,000
GBP
|
2,000,000
GBP
|
— | — |
2,000,000
GBP
|
| Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract] | ||||||||
| Exchange differences on translation [abstract] | ||||||||
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations |
4,000,000
GBP
|
— | — |
4,000,000
GBP
|
— |
1,000,000
GBP
|
— |
1,000,000
GBP
|
| Other comprehensive income | — | — | — |
12,000,000
GBP
|
— | — | — |
1,000,000
GBP
|
| Comprehensive income |
4,000,000
GBP
|
4,072,000,000
GBP
|
509,000,000
GBP
|
4,585,000,000
GBP
|
3,549,000,000
GBP
|
1,000,000
GBP
|
466,000,000
GBP
|
4,014,000,000
GBP
|