Statement Of Comprehensive Income [Abstract]
| Concept |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2023-01-01 to 2023-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
2022-01-01 to 2022-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||
| Profit (loss) |
3,509,000,000
GBP
|
— | — | — | — | — |
3,689,000,000
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 |
147,000,000
GBP
|
— | — |
147,000,000
GBP
|
— | — |
556,000,000
GBP
|
— | — |
556,000,000
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 | — |
31,000,000
GBP
|
— | — | — | — | — | — |
29,000,000
GBP
|
— |
| Other comprehensive income, before tax, exchange differences on translation of foreign operations |
17,000,000
GBP
|
— | — | — | — | — |
2,000,000
GBP
|
— | — | — |
| Cash flow hedges [abstract] | ||||||||||
| Gains (losses) on cash flow hedges, before tax | — | — |
180,000,000
GBP
|
— | — |
283,000,000
GBP
|
— | — | — | — |
| Reclassification adjustments on cash flow hedges, before tax | — | — |
110,000,000
GBP
|
— | — |
259,000,000
GBP
|
— | — | — | — |
| Other comprehensive income, before tax, cash flow hedges |
290,000,000
GBP
|
— | — | — | — | — |
542,000,000
GBP
|
— | — | — |
| Hedges of net investment in foreign operations [abstract] | ||||||||||
| Gains (losses) on hedges of net investments in foreign operations, before tax | — |
14,000,000
GBP
|
— | — | — | — | — | — |
31,000,000
GBP
|
— |
| Financial assets measured at fair value through other comprehensive income [abstract] | ||||||||||
| Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax | — | — | — | — |
-
GBP
|
— | — |
485,000,000
GBP
|
— | — |
| Reclassification adjustments on financial assets measured at fair value through other comprehensive income, before tax | — | — | — | — |
43,000,000
GBP
|
— | — |
93,000,000
GBP
|
— | — |
| Other comprehensive income, before tax, financial assets measured at fair value through other comprehensive income |
43,000,000
GBP
|
— | — | — | — | — |
392,000,000
GBP
|
— | — | — |
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] | ||||||||||
| Income tax relating to remeasurements of defined benefit plans included in other comprehensive income | — | — | — |
40,000,000
GBP
|
— | — | — | — | — |
146,000,000
GBP
|
| Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss |
40,000,000
GBP
|
— | — | — | — | — |
146,000,000
GBP
|
— | — | — |
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract] | ||||||||||
| Income tax relating to cash flow hedges included in other comprehensive income | — | — |
81,000,000
GBP
|
— | — |
152,000,000
GBP
|
— | — | — | — |
| Income tax relating to financial assets measured at fair value through other comprehensive income included in other comprehensive income | — | — | — | — |
8,000,000
GBP
|
— | — |
124,000,000
GBP
|
— | — |
| Income tax relating to components of other comprehensive income that will be reclassified to profit or loss |
73,000,000
GBP
|
— | — | — | — | — |
276,000,000
GBP
|
— | — | — |
| Other comprehensive income |
298,000,000
GBP
|
— | — | — | — | — |
1,070,000,000
GBP
|
— | — | — |
| Comprehensive income |
3,211,000,000
GBP
|
— | — | — | — | — |
2,619,000,000
GBP
|
— | — | — |
| Comprehensive income attributable to [abstract] | ||||||||||
| Comprehensive income, attributable to non-controlling interests |
1,000,000
GBP
|
— | — | — | — | — |
5,000,000
GBP
|
— | — | — |