Statement Of Financial Position [Abstract]

SANTANDER UK PLC - Filing #5588864

Concept	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2024-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2022-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31	As at 2021-12-31
Statement of financial position [abstract]
Assets [abstract]
Current assets [abstract]
Cash and cash equivalents	—	—	—	—	—	—	—	—	—	29,181,000,000 GBP	36,781,000,000 GBP	—	—	—	—	—	—	—	—	—	42,871,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	46,715,000,000 GBP	—	—	—	—	—	—	—
Assets	—	—	—	—	—	—	—	—	—	259,944,000,000 GBP	275,448,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Equity and liabilities [abstract]
Equity [abstract]
Issued capital	—	—	—	—	—	—	—	—	—	3,105,000,000 GBP	3,105,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Retained earnings	—	—	—	—	—	—	—	—	—	3,521,000,000 GBP	4,295,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Share premium	—	—	—	—	—	—	—	—	—	5,620,000,000 GBP	5,620,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Other equity interest	—	—	—	—	—	—	—	—	—	1,860,000,000 GBP	1,956,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Other reserves	—	—	—	—	—	—	—	—	—	333,000,000 GBP	353,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Equity	3,521,000,000 GBP	5,620,000,000 GBP	3,105,000,000 GBP	— GBP	1,000,000 GBP	13,773,000,000 GBP	317,000,000 GBP	1,860,000,000 GBP	17,000,000 GBP	13,773,000,000 GBP	14,623,000,000 GBP	4,295,000,000 GBP	— GBP	5,620,000,000 GBP	3,105,000,000 GBP	1,000,000 GBP	14,623,000,000 GBP	6,000,000 GBP	348,000,000 GBP	1,956,000,000 GBP	14,407,000,000 GBP	— GBP	5,620,000,000 GBP	4,848,000,000 GBP	3,105,000,000 GBP	1,000,000 GBP	14,407,000,000 GBP	1,956,000,000 GBP	5,000,000 GBP	1,128,000,000 GBP	5,053,000,000 GBP	2,191,000,000 GBP	16,102,000,000 GBP	107,000,000 GBP	25,000,000 GBP	16,102,000,000 GBP	5,620,000,000 GBP	— GBP	1,000,000 GBP	3,105,000,000 GBP
Liabilities [abstract]
Liabilities	—	—	—	—	—	—	—	—	—	246,171,000,000 GBP	260,825,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Equity and liabilities	—	—	—	—	—	—	—	—	—	259,944,000,000 GBP	275,448,000,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—