Statement Of Changes In Equity [Abstract]

United Utilities Group PLC - Filing #5038065

Concept	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	As at 2022-03-31	As at 2022-03-31	As at 2022-03-31	2021-04-01 to 2022-03-31	As at 2022-03-31	As at 2022-03-31	As at 2021-03-31	As at 2021-03-31	As at 2021-03-31	As at 2021-03-31	As at 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	As at 2020-03-31	As at 2020-03-31	As at 2020-03-31	As at 2020-03-31	As at 2020-03-31
Statement of changes in equity [abstract]
Statement of changes in equity [line items]
Equity	—	—	—	—	499,800,000 GBP	2,900,000 GBP	2,038,500,000 GBP	—	2,957,400,000 GBP	416,200,000 GBP	2,192,000,000 GBP	336,300,000 GBP	3,031,000,000 GBP	499,800,000 GBP	2,900,000 GBP	—	—	—	—	—	336,700,000 GBP	2,962,100,000 GBP	2,900,000 GBP	499,800,000 GBP	2,122,700,000 GBP
Changes in equity [abstract]
Comprehensive income [abstract]
Profit (loss)	– GBP	56,800,000 GBP	– GBP	– GBP	—	—	—	56,800,000 GBP	—	—	—	—	—	—	—	– GBP	453,400,000 GBP	– GBP	– GBP	453,400,000 GBP	—	—	—	—	—
Comprehensive income	– GBP	143,300,000 GBP	79,900,000 GBP	– GBP	—	—	—	223,200,000 GBP	—	—	—	—	—	—	—	400,000 GBP	361,200,000 GBP	– GBP	– GBP	361,600,000 GBP	—	—	—	—	—
Dividends recognised as distributions to owners	– GBP	295,500,000 GBP	– GBP	– GBP	—	—	—	295,500,000 GBP	—	—	—	—	—	—	—	– GBP	291,900,000 GBP	– GBP	– GBP	291,900,000 GBP	—	—	—	—	—
Increase (decrease) through share-based payment transactions, equity	– GBP	4,800,000 GBP	– GBP	– GBP	—	—	—	4,800,000 GBP	—	—	—	—	—	—	—	– GBP	3,600,000 GBP	– GBP	– GBP	3,600,000 GBP	—	—	—	—	—