Statement Of Comprehensive Income [Abstract]

NATIONWIDE BUILDING SOCIETY - Filing #6135789

Concept	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2024-04-05 to 2025-03-31	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04	2023-04-05 to 2024-04-04
Statement of comprehensive income [abstract]
Profit (loss)	- GBP	2,304,000,000 GBP	- GBP	- GBP	- GBP	2,338,000,000 GBP	- GBP	- GBP	2,304,000,000 GBP	34,000,000 GBP	- GBP	- GBP	1,300,000,000 GBP	- GBP	1,300,000,000 GBP	- GBP	- GBP	- GBP	- GBP	1,300,000,000 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) from investments in equity instruments	—	—	—	—	—	2,000,000 GBP	—	—	—	—	—	—	—	—	4,000,000 GBP	—	—	—	—	—
Other comprehensive income, net of tax, gains (losses) on revaluation of property, plant and equipment, right-of-use assets and intangible assets	- GBP	- GBP	1,000,000 GBP	- GBP	- GBP	1,000,000 GBP	- GBP	- GBP	1,000,000 GBP	- GBP	2,000,000 GBP	- GBP	2,000,000 GBP	- GBP	2,000,000 GBP	- GBP	- GBP	- GBP	- GBP	- GBP
Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans	- GBP	144,000,000 GBP	- GBP	- GBP	- GBP	144,000,000 GBP	- GBP	- GBP	144,000,000 GBP	- GBP	- GBP	- GBP	190,000,000 GBP	- GBP	190,000,000 GBP	- GBP	- GBP	- GBP	- GBP	190,000,000 GBP
Other comprehensive income that will not be reclassified to profit or loss, net of tax	—	—	—	—	—	145,000,000 GBP	—	—	—	—	—	—	—	—	188,000,000 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	- GBP	- GBP	- GBP	- GBP	- GBP	5,000,000 GBP	- GBP	5,000,000 GBP	5,000,000 GBP	- GBP	- GBP	49,000,000 GBP	49,000,000 GBP	- GBP	49,000,000 GBP	- GBP	- GBP	- GBP	- GBP	- GBP
Cost of hedging [abstract]
Change in value of foreign currency basis spreads [abstract]
Other comprehensive income, net of tax, change in value of foreign currency basis spreads	- GBP	- GBP	- GBP	- GBP	2,000,000 GBP	2,000,000 GBP	- GBP	- GBP	2,000,000 GBP	- GBP	- GBP	- GBP	4,000,000 GBP	- GBP	4,000,000 GBP	- GBP	- GBP	4,000,000 GBP	- GBP	- GBP
Financial assets measured at fair value through other comprehensive income [abstract]
Other comprehensive income, net of tax, financial assets measured at fair value through other comprehensive income	—	—	—	—	—	80,000,000 GBP	—	—	—	—	—	—	—	—	28,000,000 GBP	—	—	—	—	—
Other comprehensive income that will be reclassified to profit or loss, net of tax	—	—	—	—	—	77,000,000 GBP	—	—	—	—	—	—	—	—	81,000,000 GBP	—	—	—	—	—
Other comprehensive income	—	—	—	—	—	222,000,000 GBP	—	—	—	—	—	—	—	—	269,000,000 GBP	—	—	—	—	—
Comprehensive income	- GBP	2,160,000,000 GBP	1,000,000 GBP	- GBP	2,000,000 GBP	2,116,000,000 GBP	82,000,000 GBP	5,000,000 GBP	2,082,000,000 GBP	34,000,000 GBP	2,000,000 GBP	49,000,000 GBP	1,031,000,000 GBP	- GBP	1,031,000,000 GBP	- GBP	- GBP	4,000,000 GBP	24,000,000 GBP	1,110,000,000 GBP
Comprehensive income attributable to [abstract]
Comprehensive income, attributable to owners of parent	—	—	—	—	—	2,082,000,000 GBP	—	—	—	—	—	—	—	—	1,031,000,000 GBP	—	—	—	—	—
Comprehensive income, attributable to non-controlling interests	—	—	—	—	—	34,000,000 GBP	—	—	—	—	—	—	—	—	- GBP	—	—	—	—	—