Statement Of Comprehensive Income [Abstract]
| Concept |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2021-01-01 to 2021-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
2020-01-01 to 2020-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||||||||||
| Profit (loss) |
70,000,000
GBP
|
1,966,000,000
GBP
|
— | — | — | — | — | — | — |
2,036,000,000
GBP
|
1,966,000,000
GBP
|
— |
2,910,000,000
GBP
|
— | — | — |
2,798,000,000
GBP
|
— |
112,000,000
GBP
|
— | — |
2,798,000,000
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) on remeasurements of defined benefit plans | — | — | — | — | — | — | — | — | — |
59,000,000
GBP
|
— | — |
150,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | ||||||||||||||||||||||
| Exchange differences on translation [abstract] | ||||||||||||||||||||||
| Gains (losses) on exchange differences on translation of foreign operations, before tax | — | — | — | — | — | — | — | — | — |
34,000,000
GBP
|
— | — |
51,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Available-for-sale financial assets [abstract] | ||||||||||||||||||||||
| Gains (losses) on remeasuring available-for-sale financial assets, before tax | — | — | — | — | — | — | — | — | — |
—
GBP
|
— | — |
1,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss, before tax | — | — | — | — | — | — | — | — | — |
5,000,000
GBP
|
— | — |
16,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||||||||||||||
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss | — | — | — | — | — | — | — | — | — |
159,000,000
GBP
|
— | — |
21,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] | ||||||||||||||||||||||
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss | — | — | — | — | — | — | — | — | — |
7,000,000
GBP
|
— | — |
9,000,000
GBP
|
— | — | — | — | — | — | — | — | — |
| Other comprehensive income | — | — |
241,000,000
GBP
|
377,000,000
GBP
|
23,000,000
GBP
|
100,000,000
GBP
|
33,000,000
GBP
|
344,000,000
GBP
|
221,000,000
GBP
|
136,000,000
GBP
|
— |
34,000,000
GBP
|
214,000,000
GBP
|
47,000,000
GBP
|
97,000,000
GBP
|
201,000,000
GBP
|
— |
13,000,000
GBP
|
— |
221,000,000
GBP
|
171,000,000
GBP
|
— |
| Comprehensive income | — | — |
1,459,000,000
GBP
|
1,659,000,000
GBP
|
23,000,000
GBP
|
1,866,000,000
GBP
|
37,000,000
GBP
|
1,622,000,000
GBP
|
221,000,000
GBP
|
200,000,000
GBP
|
— |
146,000,000
GBP
|
1,252,000,000
GBP
|
2,751,000,000
GBP
|
97,000,000
GBP
|
1,645,000,000
GBP
|
— |
2,897,000,000
GBP
|
— |
221,000,000
GBP
|
2,627,000,000
GBP
|
— |
| Comprehensive income attributable to [abstract] | ||||||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — |
1,444,000,000
GBP
|
— | — | — | — | — | — |
178,000,000
GBP
|
— | — |
1,231,000,000
GBP
|
— | — |
1,520,000,000
GBP
|
— | — | — | — | — | — |
| Comprehensive income, attributable to non-controlling interests | — | — |
15,000,000
GBP
|
— | — | — | — | — | — |
22,000,000
GBP
|
— | — |
21,000,000
GBP
|
— | — |
125,000,000
GBP
|
— | — | — | — | — | — |