Statement Of Changes In Equity [Abstract]
| Concept |
As at 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 |
As at 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 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
2021-04-01 to 2022-03-31 |
As at 2022-03-31 |
As at 2022-03-31 |
2021-04-01 to 2022-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
2020-04-01 to 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
As at 2021-03-31 |
2020-04-01 to 2021-03-31 |
As at 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 |
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 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
As at 2020-03-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Equity |
6,000,000
GBP
|
— | — | — | — | — |
3 014
GBP
|
— | — | — | — |
4,000,000
GBP
|
3 107
GBP
|
2,000,000
GBP
|
74,000,000
GBP
|
752,000,000
GBP
|
690,000,000
GBP
|
4 597
GBP
|
— |
3 246
GBP
|
139,000,000
GBP
|
— |
6,000,000
GBP
|
4 523
GBP
|
2 967
GBP
|
74,000,000
GBP
|
690,000,000
GBP
|
— |
–
GBP
|
8,000,000
GBP
|
118,000,000
GBP
|
3 014
GBP
|
2 849
GBP
|
— |
578,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
113,000,000
GBP
|
2 890
GBP
|
4 327
GBP
|
–
GBP
|
3 014
GBP
|
3 003
GBP
|
815,000,000
GBP
|
6,000,000
GBP
|
690,000,000
GBP
|
8,000,000
GBP
|
74,000,000
GBP
|
| Changes in equity [abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Profit (loss) | — |
151,000,000
GBP
|
–
GBP
|
19,000,000
GBP
|
–
GBP
|
151,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
170,000,000
GBP
|
— | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
79,000,000
GBP
|
–
GBP
|
–
GBP
|
68,000,000
GBP
|
–
GBP
|
11,000,000
GBP
|
68,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Other comprehensive income | — |
107,000,000
GBP
|
–
GBP
|
11,000,000
GBP
|
1 74
GBP
|
77,000,000
GBP
|
— |
4,000,000
GBP
|
–
GBP
|
6,000,000
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
118,000,000
GBP
|
— | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— |
237,000,000
GBP
|
–
GBP
|
108,000,000
GBP
|
–
GBP
|
–
GBP
|
1 24
GBP
|
–
GBP
|
5,000,000
GBP
|
113,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Comprehensive income | — |
258,000,000
GBP
|
–
GBP
|
30,000,000
GBP
|
1 74
GBP
|
74,000,000
GBP
|
— |
4,000,000
GBP
|
–
GBP
|
6,000,000
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
288,000,000
GBP
|
— | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— |
237,000,000
GBP
|
–
GBP
|
29,000,000
GBP
|
–
GBP
|
–
GBP
|
192,000,000
GBP
|
–
GBP
|
16,000,000
GBP
|
45,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Dividends recognised as distributions to owners | — |
–
GBP
|
–
GBP
|
12,000,000
GBP
|
–
GBP
|
–
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
12,000,000
GBP
|
— | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
8,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
8,000,000
GBP
|
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Increase (decrease) through changes in ownership interests in subsidiaries that do not result in loss of control, equity | — |
1,000,000
GBP
|
–
GBP
|
3,000,000
GBP
|
–
GBP
|
1,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
2,000,000
GBP
|
— | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
4,000,000
GBP
|
–
GBP
|
3,000,000
GBP
|
4,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
| Increase (decrease) through share-based payment transactions, equity | — |
1,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
1,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — |
1,000,000
GBP
|
— | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— | — | — | — | — |
–
GBP
|
— |
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — |