Statement Of Comprehensive Income [Abstract]
| Concept |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||||||
| Profit (loss) |
–
GBP
|
–
GBP
|
283,000,000
GBP
|
13,000,000
GBP
|
–
GBP
|
270,000,000
GBP
|
–
GBP
|
270,000,000
GBP
|
–
GBP
|
–
GBP
|
11,000,000
GBP
|
–
GBP
|
6,000,000
GBP
|
–
GBP
|
5,000,000
GBP
|
–
GBP
|
11,000,000
GBP
|
–
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 | — | — |
3,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
2,000,000
GBP
|
— | — | — | — | — |
| Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans | — | — |
2 0
GBP
|
— | — | — | — | — | — | — | — | — |
12,000,000
GBP
|
— | — | — | — | — |
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | ||||||||||||||||||
| Exchange differences on translation [abstract] | ||||||||||||||||||
| Reclassification adjustments on exchange differences on translation of foreign operations, before tax | — | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
99,000,000
GBP
|
— | — | — | — | — |
| Other comprehensive income, before tax, exchange differences on translation of foreign operations | — | — |
13 3
GBP
|
— | — | — | — | — | — | — | — | — |
13 3
GBP
|
— | — | — | — | — |
| Cash flow hedges [abstract] | ||||||||||||||||||
| Other comprehensive income, before tax, cash flow hedges | — | — |
4 8
GBP
|
— | — | — | — | — | — | — | — | — |
9,000,000
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 | — | — |
–
GBP
|
— | — | — | — | — | — | — | — | — |
–
GBP
|
— | — | — | — | — |
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] | ||||||||||||||||||
| Income tax relating to cash flow hedges included in other comprehensive income | — | — |
17,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
7,000,000
GBP
|
— | — | — | — | — |
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss | — | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
–
GBP
|
— | — | — | — | — |
| Other comprehensive income |
–
GBP
|
–
GBP
|
15 3
GBP
|
3,000,000
GBP
|
–
GBP
|
2 0
GBP
|
–
GBP
|
15 0
GBP
|
13 0
GBP
|
–
GBP
|
282,000,000
GBP
|
294,000,000
GBP
|
288,000,000
GBP
|
–
GBP
|
6,000,000
GBP
|
–
GBP
|
12,000,000
GBP
|
–
GBP
|
| Comprehensive income |
–
GBP
|
–
GBP
|
13 0
GBP
|
10,000,000
GBP
|
–
GBP
|
25 0
GBP
|
–
GBP
|
12 0
GBP
|
13 0
GBP
|
–
GBP
|
2 71
GBP
|
2 94
GBP
|
282,000,000
GBP
|
–
GBP
|
11,000,000
GBP
|
–
GBP
|
23,000,000
GBP
|
–
GBP
|
| Comprehensive income attributable to [abstract] | ||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — |
12 0
GBP
|
— | — | — | — | — | — | — | — | — |
2 71
GBP
|
— | — | — | — | — |
| Comprehensive income, attributable to non-controlling interests | — | — |
10,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
11,000,000
GBP
|
— | — | — | — | — |