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 |
2022-01-01 to 2022-12-31 |
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | |||||||||||||||||
| Profit (loss) |
1,541,000,000
GBP
|
— |
1,541,000,000
GBP
|
1,541,000,000
GBP
|
— | — |
1,394,000,000
GBP
|
1,394,000,000
GBP
|
— |
1,394,000,000
GBP
|
—
GBP
|
19,000,000
GBP
|
— | — |
1,365,000,000
GBP
|
1,384,000,000
GBP
|
1,365,000,000
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 |
598,000,000
GBP
|
— | — | — | — | — | — |
722,000,000
GBP
|
— | — | — | — | — | — | — |
1,264,000,000
GBP
|
— |
| Other comprehensive income, before tax, change in fair value of financial liability attributable to change in credit risk of liability |
15,000,000
GBP
|
— | — | — | — | — | — |
29,000,000
GBP
|
— | — | — | — | — | — | — |
—
GBP
|
— |
| Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract] | |||||||||||||||||
| Cash flow hedges [abstract] | |||||||||||||||||
| Gains (losses) on cash flow hedges, before tax |
169,000,000
GBP
|
— | — | — | — | — | — |
425,000,000
GBP
|
— | — | — | — | — | — | — |
873,000,000
GBP
|
— |
| Reclassification adjustments on cash flow hedges, before tax |
1,248,000,000
GBP
|
— | — | — | — | — | — |
2,129,000,000
GBP
|
— | — | — | — | — | — | — |
358,000,000
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 |
89,000,000
GBP
|
— | — | — | — | — | — |
278,000,000
GBP
|
— | — | — | — | — | — | — |
111,000,000
GBP
|
— |
| Reclassification adjustments on financial assets measured at fair value through other comprehensive income, before tax |
105,000,000
GBP
|
— | — | — | — | — | — |
247,000,000
GBP
|
— | — | — | — | — | — | — |
110,000,000
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 |
167,000,000
GBP
|
— | — | — | — | — | — |
267,000,000
GBP
|
— | — | — | — | — | — | — |
419,000,000
GBP
|
— |
| Income tax relating to changes in fair value of financial liability attributable to change in credit risk of liability included in other comprehensive income |
4,000,000
GBP
|
— | — | — | — | — | — |
9,000,000
GBP
|
— | — | — | — | — | — | — |
—
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 |
299,000,000
GBP
|
— | — | — | — | — | — |
469,000,000
GBP
|
— | — | — | — | — | — | — |
141,000,000
GBP
|
— |
| Income tax relating to financial assets measured at fair value through other comprehensive income included in other comprehensive income |
5,000,000
GBP
|
— | — | — | — | — | — |
11,000,000
GBP
|
— | — | — | — | — | — | — |
2,000,000
GBP
|
— |
| Other comprehensive income |
327,000,000
GBP
|
780,000,000
GBP
|
442,000,000
GBP
|
327,000,000
GBP
|
11,000,000
GBP
|
1,235,000,000
GBP
|
1,690,000,000
GBP
|
1,690,000,000
GBP
|
20,000,000
GBP
|
435,000,000
GBP
|
— | — |
374,000,000
GBP
|
3,000,000
GBP
|
468,000,000
GBP
|
468,000,000
GBP
|
845,000,000
GBP
|
| Comprehensive income |
1,868,000,000
GBP
|
780,000,000
GBP
|
1,099,000,000
GBP
|
1,868,000,000
GBP
|
11,000,000
GBP
|
1,235,000,000
GBP
|
296,000,000
GBP
|
296,000,000
GBP
|
20,000,000
GBP
|
959,000,000
GBP
|
—
GBP
|
19,000,000
GBP
|
374,000,000
GBP
|
3,000,000
GBP
|
1,833,000,000
GBP
|
1,852,000,000
GBP
|
2,210,000,000
GBP
|
| Comprehensive income attributable to [abstract] | |||||||||||||||||
| Comprehensive income, attributable to owners of parent |
1,868,000,000
GBP
|
— | — | — | — | — | — |
296,000,000
GBP
|
— | — | — | — | — | — | — |
1,833,000,000
GBP
|
— |
| Comprehensive income, attributable to non-controlling interests |
—
GBP
|
— | — | — | — | — | — |
—
GBP
|
— | — | — | — | — | — | — |
19,000,000
GBP
|
— |