Statement Of Financial Position [Abstract]
| Concept |
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 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
As at 2019-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of financial position [abstract] | ||||||||||||||||||||||||||||
| Assets [abstract] | ||||||||||||||||||||||||||||
| Property, plant and equipment | — | — | — | — | — |
187,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
236,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Investments accounted for using equity method | — | — | — | — | — |
274,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,371,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current tax assets | — | — | — | — | — |
2,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
9,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Deferred tax assets | — | — | — | — | — |
168,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
131,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Trade and other receivables | — | — | — | — | — |
680,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
621,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Cash and cash equivalents | — | — | — | — | — |
1,904,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,519,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Assets | — | — | — | — | — |
11,418,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
10,478,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity and liabilities [abstract] | ||||||||||||||||||||||||||||
| Equity [abstract] | ||||||||||||||||||||||||||||
| Issued capital | — | — | — | — | — |
305,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
306,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Retained earnings | — | — | — | — | — |
5,775,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
4,970,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Share premium | — | — | — | — | — |
640,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
640,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Treasury shares | — | — | — | — | — |
171,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
170,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Other reserves | — | — | — | — | — |
1,094,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,064,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity attributable to owners of parent | — | — | — | — | — |
7,643,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
6,810,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity |
5,775,000,000
GBP
|
171,000,000
GBP
|
1,094,000,000
GBP
|
207,000,000
GBP
|
6,000,000
GBP
|
7,856,000,000
GBP
|
7,643,000,000
GBP
|
640,000,000
GBP
|
305,000,000
GBP
|
4,970,000,000
GBP
|
6,810,000,000
GBP
|
306,000,000
GBP
|
–
GBP
|
3,000,000
GBP
|
–
GBP
|
170,000,000
GBP
|
1,064,000,000
GBP
|
640,000,000
GBP
|
6,813,000,000
GBP
|
6,564,000,000
GBP
|
2,845,000,000
GBP
|
640,000,000
GBP
|
6,666,000,000
GBP
|
2,886,000,000
GBP
|
99,000,000
GBP
|
3,000,000
GBP
|
134,000,000
GBP
|
327,000,000
GBP
|
| Liabilities [abstract] | ||||||||||||||||||||||||||||
| Provisions [abstract] | ||||||||||||||||||||||||||||
| Provisions | — | — | — | — | — |
49,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
93,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Other financial liabilities | — | — | — | — | — |
1,046,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
1,177,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Current tax liabilities | — | — | — | — | — |
27,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
15,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Deferred tax liabilities | — | — | — | — | — |
165,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
66,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Liabilities included in disposal groups classified as held for sale | — | — | — | — | — |
–
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
11,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Liabilities | — | — | — | — | — |
3,562,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
3,665,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Equity and liabilities | — | — | — | — | — |
11,418,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — | — | — |
10,478,000,000
GBP
|
— | — | — | — | — | — | — | — | — |