Statement Of Comprehensive Income [Abstract]
| Concept |
2021-03-28 to 2022-04-02 |
2021-03-28 to 2022-04-02 |
2021-03-28 to 2022-04-02 |
2021-03-28 to 2022-04-02 |
2021-03-28 to 2022-04-02 |
2021-03-28 to 2022-04-02 |
2021-03-28 to 2022-04-02 |
2020-03-29 to 2021-03-27 |
2020-03-29 to 2021-03-27 |
2020-03-29 to 2021-03-27 |
2020-03-29 to 2021-03-27 |
2020-03-29 to 2021-03-27 |
2020-03-29 to 2021-03-27 |
2020-03-29 to 2021-03-27 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Statement of comprehensive income [abstract] | ||||||||||||||
| Profit (loss) |
397,000,000
GBP
|
–
GBP
|
–
GBP
|
396,000,000
GBP
|
396,000,000
GBP
|
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
376,000,000
GBP
|
–
GBP
|
–
GBP
|
376,000,000
GBP
|
376,000,000
GBP
|
| Other comprehensive income [abstract] | ||||||||||||||
| Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract] | ||||||||||||||
| Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans |
–
GBP
|
— | — | — | — | — | — |
–
GBP
|
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
1,000,000
GBP
|
1,000,000
GBP
|
| Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract] | ||||||||||||||
| Cash flow hedges [abstract] | ||||||||||||||
| Other comprehensive income, net of tax, cash flow hedges |
1,000,000
GBP
|
1,000,000
GBP
|
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
–
GBP
|
— | — |
–
GBP
|
— | — | — | — |
| Other comprehensive income |
21,000,000
GBP
|
— | — | — | — | — | — | — | — |
48,000,000
GBP
|
— | — | — | — |
| Comprehensive income |
418,000,000
GBP
|
21,000,000
GBP
|
–
GBP
|
417,000,000
GBP
|
3 96
GBP
|
–
GBP
|
1,000,000
GBP
|
–
GBP
|
–
GBP
|
328,000,000
GBP
|
–
GBP
|
49,000,000
GBP
|
328,000,000
GBP
|
377,000,000
GBP
|
| Comprehensive income attributable to [abstract] | ||||||||||||||
| Comprehensive income, attributable to owners of parent |
417,000,000
GBP
|
— | — | — | — | — | — | — | — |
328,000,000
GBP
|
— | — | — | — |
| Comprehensive income, attributable to non-controlling interests |
1,000,000
GBP
|
— | — | — | — | — | — | — | — |
–
GBP
|
— | — | — | — |