Statement Of Financial Position [Abstract]
| Concept |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2022-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2021-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
As at 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||||||||||||
| Property, plant and equipment |
2,599,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
2,528,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Investments accounted for using equity method |
62,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
87,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Deferred tax assets |
373,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
250,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Cash and cash equivalents |
355,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
473,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Assets |
13,987,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
14,022,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||||||||||||
| Issued capital |
309,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
333,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Retained earnings |
4,379,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
5,319,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Share premium |
3,271,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
3,271,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Other reserves |
2,330,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
2,330,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent |
7,129,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
7,507,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Non-controlling interests |
39,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
33,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Equity |
7,168,000,000
GBP
|
2,330,000,000
GBP
|
39,000,000
GBP
|
3,271,000,000
GBP
|
753,000,000
GBP
|
4,379,000,000
GBP
|
309,000,000
GBP
|
638,000,000
GBP
|
109,000,000
GBP
|
7,129,000,000
GBP
|
5,319,000,000
GBP
|
729,000,000
GBP
|
2,330,000,000
GBP
|
7,540,000,000
GBP
|
109,000,000
GBP
|
7,507,000,000
GBP
|
3,271,000,000
GBP
|
33,000,000
GBP
|
76,000,000
GBP
|
333,000,000
GBP
|
861,000,000
GBP
|
29,000,000
GBP
|
7,081,000,000
GBP
|
333,000,000
GBP
|
109,000,000
GBP
|
30,000,000
GBP
|
2,330,000,000
GBP
|
8,138,000,000
GBP
|
7,110,000,000
GBP
|
–
GBP
|
| Liabilities [abstract] | ||||||||||||||||||||||||||||||
| Deferred tax liabilities |
619,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
614,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| Liabilities |
6,819,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
6,482,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |