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 |
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) |
15 4
GBP
|
–
GBP
|
–
GBP
|
1 ,9 12
GBP
|
–
GBP
|
–
GBP
|
1, 75 8
GBP
|
1, 912
GBP
|
1, 7 5 8
GBP
|
1, 2 9 9
GBP
|
–
GBP
|
1, 3 71
GBP
|
72,000,000
GBP
|
–
GBP
|
–
GBP
|
1, 2 9 9
GBP
|
–
GBP
|
1, 3 71
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 | — | — |
–
GBP
|
2 , 4 51
GBP
|
— | — | — |
2 , 4 51
GBP
|
— | — | — |
1, 3 6 1
GBP
|
— |
–
GBP
|
— | — | — |
1 , 3 61
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 | — | — |
32,000,000
GBP
|
–
GBP
|
— | — | — |
32,000,000
GBP
|
— | — | — |
2 24
GBP
|
— |
224,000,000
GBP
|
— | — | — |
–
GBP
|
| Reclassification adjustments on exchange differences on translation of foreign operations, before tax | — | — |
9,000,000
GBP
|
–
GBP
|
— | — | — |
9,000,000
GBP
|
— | — | — |
35,000,000
GBP
|
— |
35,000,000
GBP
|
— | — | — |
–
GBP
|
| Cash flow hedges [abstract] | ||||||||||||||||||
| Gains (losses) on cash flow hedges, before tax | — | — |
11,000,000
GBP
|
–
GBP
|
— | — | — |
11,000,000
GBP
|
— | — | — |
46,000,000
GBP
|
— |
46,000,000
GBP
|
— | — | — |
–
GBP
|
| Reclassification adjustments on cash flow hedges, before tax | — | — |
3 2
GBP
|
–
GBP
|
— | — | — |
32,000,000
GBP
|
— | — | — |
42,000,000
GBP
|
— |
42,000,000
GBP
|
— | — | — |
–
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 | — | — |
–
GBP
|
39 4
GBP
|
— | — | — |
3 94
GBP
|
— | — | — |
33 0
GBP
|
— |
–
GBP
|
— | — | — |
330,000,000
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 | — | — |
4,000,000
GBP
|
–
GBP
|
— | — | — |
4,000,000
GBP
|
— | — | — |
16,000,000
GBP
|
— |
1 6
GBP
|
— | — | — |
–
GBP
|
| Other comprehensive income |
2,000,000
GBP
|
–
GBP
|
2,000,000
GBP
|
2 ,1 2 1
GBP
|
3,000,000
GBP
|
–
GBP
|
2 ,12 1
GBP
|
2 ,1 2 3
GBP
|
2 ,12 4
GBP
|
1, 0 8 6
GBP
|
–
GBP
|
1, 27 6
GBP
|
14,000,000
GBP
|
19 0
GBP
|
–
GBP
|
1, 2 6 2
GBP
|
17 6
GBP
|
1, 0 8 6
GBP
|
| Comprehensive income |
15 6
GBP
|
–
GBP
|
2,000,000
GBP
|
4 ,033
GBP
|
3,000,000
GBP
|
–
GBP
|
3, 879
GBP
|
4,035,000,000
GBP
|
3,8 82
GBP
|
213,000,000
GBP
|
–
GBP
|
95,000,000
GBP
|
58,000,000
GBP
|
19 0
GBP
|
–
GBP
|
37,000,000
GBP
|
17 6
GBP
|
285,000,000
GBP
|
| Comprehensive income attributable to [abstract] | ||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — |
3,000,000
GBP
|
3,882,000,000
GBP
|
— | — | — |
3, 879
GBP
|
— | — | — |
37,000,000
GBP
|
— |
17 6
GBP
|
— | — | — |
213,000,000
GBP
|
| Comprehensive income, attributable to non-controlling interests | — | — |
5,000,000
GBP
|
151,000,000
GBP
|
— | — | — |
15 6
GBP
|
— | — | — |
58,000,000
GBP
|
— |
14,000,000
GBP
|
— | — | — |
72,000,000
GBP
|