Statement Of Changes In Equity [Abstract]
| Concept |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
As at 2023-09-30 |
As at 2023-09-30 |
As at 2023-09-30 |
2022-10-01 to 2023-09-30 |
2022-10-01 to 2023-09-30 |
As at 2023-09-30 |
As at 2023-09-30 |
2022-10-01 to 2023-09-30 |
As at 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
As at 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
2021-10-01 to 2022-09-30 |
As at 2022-09-30 |
2021-10-01 to 2022-09-30 |
As at 2022-09-30 |
As at 2022-09-30 |
2021-10-01 to 2022-09-30 |
As at 2021-09-30 |
As at 2021-09-30 |
As at 2021-09-30 |
As at 2021-09-30 |
As at 2021-09-30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of changes in equity [abstract] | |||||||||||||||||||||||||||||
| Statement of changes in equity [line items] | |||||||||||||||||||||||||||||
| Equity | — | — | — | — |
658,000,000
GBP
|
548,000,000
GBP
|
189,000,000
GBP
|
— | — |
12,000,000
GBP
|
1,407,000,000
GBP
|
— |
267,000,000
GBP
|
— | — |
548,000,000
GBP
|
— | — | — |
1,397,000,000
GBP
|
— |
570,000,000
GBP
|
12,000,000
GBP
|
— |
103,000,000
GBP
|
448,000,000
GBP
|
1,111,000,000
GBP
|
12,000,000
GBP
|
548,000,000
GBP
|
| Changes in equity [abstract] | |||||||||||||||||||||||||||||
| Comprehensive income [abstract] | |||||||||||||||||||||||||||||
| Profit (loss) |
211,000,000
GBP
|
329,000,000
GBP
|
118,000,000
GBP
|
–
GBP
|
— | — | — |
–
GBP
|
–
GBP
|
— | — |
211,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
— |
260,000,000
GBP
|
263,000,000
GBP
|
3,000,000
GBP
|
— |
–
GBP
|
— | — |
260,000,000
GBP
|
— | — | — | — | — |
| Other comprehensive income | — | — | — | — | — | — | — | — | — | — | — |
78,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — |
197,000,000
GBP
|
— | — | — | — | — |
| Comprehensive income |
211,000,000
GBP
|
— | — |
–
GBP
|
— | — | — |
78,000,000
GBP
|
–
GBP
|
— | — |
133,000,000
GBP
|
— |
164,000,000
GBP
|
–
GBP
|
— |
293,000,000
GBP
|
— | — | — |
–
GBP
|
— | — |
457,000,000
GBP
|
— | — | — | — | — |
| Dividends recognised as distributions to owners |
190,000,000
GBP
|
— | — |
–
GBP
|
— | — | — |
–
GBP
|
–
GBP
|
— | — |
190,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
— |
183,000,000
GBP
|
— | — | — |
–
GBP
|
— | — |
183,000,000
GBP
|
— | — | — | — | — |
| Increase (decrease) through treasury share transactions, equity |
11,000,000
GBP
|
— | — |
–
GBP
|
— | — | — |
–
GBP
|
–
GBP
|
— | — |
11,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
— |
7,000,000
GBP
|
— | — | — |
–
GBP
|
— | — |
7,000,000
GBP
|
— | — | — | — | — |
| Increase (decrease) through share-based payment transactions, equity |
57,000,000
GBP
|
— | — |
–
GBP
|
— | — | — |
–
GBP
|
–
GBP
|
— | — |
57,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
— |
37,000,000
GBP
|
— | — | — |
–
GBP
|
— | — |
37,000,000
GBP
|
— | — | — | — | — |
| Increase (decrease) in equity |
123,000,000
GBP
|
— | — |
–
GBP
|
— | — | — |
–
GBP
|
–
GBP
|
— | — |
123,000,000
GBP
|
— |
–
GBP
|
–
GBP
|
— |
171,000,000
GBP
|
— | — | — |
–
GBP
|
— | — |
171,000,000
GBP
|
— | — | — | — | — |