Statement Of Cash Flows [Abstract]
| Concept |
As at 2021-12-31 |
2021-01-01 to 2021-12-31 |
As at 2020-12-31 |
2020-01-01 to 2020-12-31 |
As at 2019-12-31 |
|---|---|---|---|---|---|
| Statement of cash flows [abstract] | |||||
| Cash flows from (used in) operating activities [abstract] | |||||
| Cash flows from (used in) operations | — |
3 ,1 0 3
GBP
|
— |
1, 4 7 3
GBP
|
— |
| Income taxes paid (refund), classified as operating activities | — |
10,000,000
GBP
|
— |
28,000,000
GBP
|
— |
| Cash flows from (used in) operating activities | — |
3,0 93
GBP
|
— |
1, 4 4 5
GBP
|
— |
| Cash flows from (used in) investing activities [abstract] | |||||
| Cash flows from losing control of subsidiaries or other businesses, classified as investing activities | — |
218,000,000
GBP
|
— |
3,000,000
GBP
|
— |
| Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities | — |
7,000,000
GBP
|
— |
20,000,000
GBP
|
— |
| Purchase of property, plant and equipment, classified as investing activities | — |
13,000,000
GBP
|
— |
28,000,000
GBP
|
— |
| Purchase of intangible assets, classified as investing activities | — |
–
GBP
|
— |
4,000,000
GBP
|
— |
| Cash flows from (used in) investing activities | — |
2,6 41
GBP
|
— |
1, 4 74
GBP
|
— |
| Cash flows from (used in) financing activities [abstract] | |||||
| Payments to acquire or redeem entity's shares | — |
–
GBP
|
— |
41,000,000
GBP
|
— |
| Payments of lease liabilities, classified as financing activities | — |
10,000,000
GBP
|
— |
14,000,000
GBP
|
— |
| Interest paid, classified as financing activities | — |
2,000,000
GBP
|
— |
2,000,000
GBP
|
— |
| Cash flows from (used in) financing activities | — |
307,000,000
GBP
|
— |
305,000,000
GBP
|
— |
| Increase (decrease) in cash and cash equivalents before effect of exchange rate changes | — |
14 5
GBP
|
— |
334,000,000
GBP
|
— |
| Effect of exchange rate changes on cash and cash equivalents [abstract] | |||||
| Effect of exchange rate changes on cash and cash equivalents | — |
2,000,000
GBP
|
— |
2,000,000
GBP
|
— |
| Cash and cash equivalents |
2,06 4
GBP
|
— |
1,9 21
GBP
|
— |
2, 253
GBP
|