Statement Of Cash Flows [Abstract]
| Concept |
2024-01-01 to 2024-12-31 |
2024-01-01 to 2024-12-31 |
As at 2024-12-31 |
2024-01-01 to 2024-12-31 |
2024-01-01 to 2024-12-31 |
2023-01-01 to 2023-12-31 |
As at 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|
| Statement of cash flows [abstract] | ||||||||||
| Cash flows from (used in) operating activities [abstract] | ||||||||||
| Profit (loss) |
14,000,000
GBP
|
435,000,000
GBP
|
— |
421,000,000
GBP
|
421,000,000
GBP
|
283,000,000
GBP
|
— |
13,000,000
GBP
|
270,000,000
GBP
|
270,000,000
GBP
|
| Cash flows from (used in) operations | — |
873,000,000
GBP
|
— | — | — |
900,000,000
GBP
|
— | — | — | — |
| Interest paid, classified as operating activities | — |
215,000,000
GBP
|
— | — | — |
197,000,000
GBP
|
— | — | — | — |
| Interest received, classified as operating activities | — |
62,000,000
GBP
|
— | — | — |
46,000,000
GBP
|
— | — | — | — |
| Income taxes paid (refund), classified as operating activities | — |
134,000,000
GBP
|
— | — | — |
156,000,000
GBP
|
— | — | — | — |
| Cash flows from (used in) operating activities | — |
586,000,000
GBP
|
— | — | — |
593,000,000
GBP
|
— | — | — | — |
| Cash flows from (used in) investing activities [abstract] | ||||||||||
| Cash flows from losing control of subsidiaries or other businesses, classified as investing activities | — |
391,000,000
GBP
|
— | — | — |
1,000,000
GBP
|
— | — | — | — |
| Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities | — |
5,000,000
GBP
|
— | — | — |
137,000,000
GBP
|
— | — | — | — |
| Proceeds from sales of property, plant and equipment, classified as investing activities | — |
9,000,000
GBP
|
— | — | — |
31,000,000
GBP
|
— | — | — | — |
| Purchase of property, plant and equipment, classified as investing activities | — |
76,000,000
GBP
|
— | — | — |
88,000,000
GBP
|
— | — | — | — |
| Purchase of intangible assets, classified as investing activities | — |
3,000,000
GBP
|
— | — | — |
5,000,000
GBP
|
— | — | — | — |
| Cash flows from (used in) investing activities | — |
328,000,000
GBP
|
— | — | — |
195,000,000
GBP
|
— | — | — | — |
| Cash flows from (used in) financing activities [abstract] | ||||||||||
| Payments from changes in ownership interests in subsidiaries that do not result in loss of control | — |
—
GBP
|
— | — | — |
15,000,000
GBP
|
— | — | — | — |
| Payments of lease liabilities, classified as financing activities | — |
81,000,000
GBP
|
— | — | — |
87,000,000
GBP
|
— | — | — | — |
| Cash flows from (used in) financing activities | — |
890,000,000
GBP
|
— | — | — |
934,000,000
GBP
|
— | — | — | — |
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — |
24,000,000
GBP
|
— | — | — |
536,000,000
GBP
|
— | — | — | — |
| Effect of exchange rate changes on cash and cash equivalents [abstract] | ||||||||||
| Effect of exchange rate changes on cash and cash equivalents | — |
98,000,000
GBP
|
— | — | — |
74,000,000
GBP
|
— | — | — | — |
| Cash and cash equivalents | — | — |
549,000,000
GBP
|
— | — | — |
689,000,000
GBP
|
— | — | — |