Statement Of Comprehensive Income [Abstract]
| Concept |
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 |
2021-04-01 to 2022-03-31 |
2021-04-01 to 2022-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
2020-04-01 to 2021-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
101,000,000
GBP
|
–
GBP
|
–
GBP
|
101,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
205,000,000
GBP
|
205,000,000
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) from investments in equity instruments |
–
GBP
|
–
GBP
|
–
GBP
|
5,000,000
GBP
|
–
GBP
|
5,000,000
GBP
|
–
GBP
|
5,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
5,000,000
GBP
|
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans |
–
GBP
|
–
GBP
|
177,000,000
GBP
|
–
GBP
|
–
GBP
|
177,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
141,000,000
GBP
|
141,000,000
GBP
|
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | ||||||||||||
| Hedges of net investment in foreign operations [abstract] | ||||||||||||
| Other comprehensive income, before tax, hedges of net investments in foreign operations | — | — | — | — | — |
2,000,000
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 components of other comprehensive income that will not be reclassified to profit or loss | — | — | — | — | — |
35,000,000
GBP
|
— | — | — | — | — |
28,000,000
GBP
|
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] | ||||||||||||
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss | — | — | — | — | — |
10,000,000
GBP
|
— | — | — | — | — |
–
GBP
|
| Other comprehensive income | — | — | — | — | — |
189,000,000
GBP
|
— | — | — | — | — |
255,000,000
GBP
|
| Comprehensive income |
–
GBP
|
–
GBP
|
41,000,000
GBP
|
47,000,000
GBP
|
–
GBP
|
88,000,000
GBP
|
–
GBP
|
1 42
GBP
|
–
GBP
|
–
GBP
|
92,000,000
GBP
|
50,000,000
GBP
|