Analysis Of Income And Expense [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 |
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 |
2019-01-01 to 2019-12-31 |
2019-01-01 to 2019-12-31 |
2019-01-01 to 2019-12-31 |
2019-01-01 to 2019-12-31 |
2019-01-01 to 2019-12-31 |
2019-01-01 to 2019-12-31 |
2019-01-01 to 2019-12-31 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Analysis of income and expense [abstract] | |||||||||||||||||||||
| Revenue [abstract] | |||||||||||||||||||||
| Interest income | — | — | — | — | — |
4,762,000,000
GBP
|
— |
5,031,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
5,817,000,000
GBP
|
— | — |
| Material income and expense [abstract] | |||||||||||||||||||||
| Interest expense | — | — | — | — | — |
813,000,000
GBP
|
— |
1,643,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
2,593,000,000
GBP
|
— | — |
| Interest income (expense) | — | — | — | — | — |
3,949,000,000
GBP
|
— |
3,388,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
3,224,000,000
GBP
|
— | — |
| Other operating income (expense) | — | — | — | — | — |
264,000,000
GBP
|
— |
145,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
187,000,000
GBP
|
— | — |
| Revenue and other operating income | — | — | — | — | — |
4,499,000,000
GBP
|
— |
3,852,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
4,035,000,000
GBP
|
— | — |
| Fee and commission income (expense) [abstract] | |||||||||||||||||||||
| Fee and commission income [abstract] | |||||||||||||||||||||
| Fee and commission income | — | — | — | — | — |
697,000,000
GBP
|
— |
680,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
1,038,000,000
GBP
|
— | — |
| Fee and commission expense [abstract] | |||||||||||||||||||||
| Fee and commission expense | — | — | — | — | — |
411,000,000
GBP
|
— |
361,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
414,000,000
GBP
|
— | — |
| Fee and commission income (expense) | — | — | — | — | — |
286,000,000
GBP
|
— |
319,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
624,000,000
GBP
|
— | — |
| Miscellaneous other comprehensive income [abstract] | |||||||||||||||||||||
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations and hedges of net investments in foreign operations [abstract] | |||||||||||||||||||||
| Other comprehensive income, net of tax, exchange differences on translation of foreign operations | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
4,000,000
GBP
|
4,000,000
GBP
|
— | — |
4,000,000
GBP
|
— | — |
| Comprehensive income, continuing and discontinued operations [abstract] | |||||||||||||||||||||
| Comprehensive income |
19,000,000
GBP
|
374,000,000
GBP
|
1,833,000,000
GBP
|
—
GBP
|
3,000,000
GBP
|
1,852,000,000
GBP
|
2,210,000,000
GBP
|
211,000,000
GBP
|
79,000,000
GBP
|
5,000,000
GBP
|
110,000,000
GBP
|
—
GBP
|
17,000,000
GBP
|
194,000,000
GBP
|
4,000,000
GBP
|
374,000,000
GBP
|
263,000,000
GBP
|
21,000,000
GBP
|
395,000,000
GBP
|
—
GBP
|
115,000,000
GBP
|
| Comprehensive income attributable to owners of parent, continuing and discontinued operations [abstract] | |||||||||||||||||||||
| Comprehensive income, attributable to owners of parent | — | — | — | — | — |
1,833,000,000
GBP
|
— |
194,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
374,000,000
GBP
|
— | — |
| Comprehensive income attributable to non-controlling interests, continuing and discontinued operations [abstract] | |||||||||||||||||||||
| Comprehensive income, attributable to non-controlling interests | — | — | — | — | — |
19,000,000
GBP
|
— |
17,000,000
GBP
|
— | — | — | — | — | — | — | — | — | — |
21,000,000
GBP
|
— | — |