Statement Of Changes In Equity [Abstract]

Halma PLC - Filing #1899639

Concept	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	As at 2023-03-31	As at 2023-03-31	As at 2023-03-31	As at 2023-03-31	As at 2023-03-31	As at 2023-03-31	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	As at 2023-03-31	As at 2023-03-31	2022-04-01 to 2023-03-31	2022-04-01 to 2023-03-31	As at 2023-03-31	2022-04-01 to 2023-03-31	As at 2023-03-31	As at 2022-03-31	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	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	2021-04-01 to 2022-03-31	As at 2022-03-31	As at 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	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	As at 2022-03-31	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	As at 2021-04-01	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	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	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	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
Statement of changes in equity [abstract]
Statement of changes in equity [line items]
Equity	—	—	—	—	1,598,900,000 GBP	23,600,000 GBP	38,000,000 GBP	46,100,000 GBP	200,000 GBP	600,000 GBP	—	—	—	—	—	100,000 GBP	1,415,800,000 GBP	—	—	162,300,000 GBP	—	4,400,000 GBP	200,000 GBP	—	—	—	—	—	—	—	—	1,700,000 GBP	30,700,000 GBP	—	400,000 GBP	38,000,000 GBP	117,100,000 GBP	1,403,100,000 GBP	400,000 GBP	—	23,600,000 GBP	—	—	1,256,600,000 GBP	1,052,200,000 GBP	23,600,000 GBP	600,000 GBP	38,000,000 GBP	1,167,600,000 GBP	– GBP	20,900,000 GBP	700,000 GBP	73,200,000 GBP	200,000 GBP	– GBP	– GBP	– GBP	– GBP	700,000 GBP	600,000 GBP	200,000 GBP	– GBP	13,600,000 GBP	– GBP	20,900,000 GBP	13,600,000 GBP	38,000,000 GBP	1,065,800,000 GBP	1,167,600,000 GBP	– GBP	– GBP	13,600,000 GBP	73,200,000 GBP	23,600,000 GBP
Changes in equity [abstract]
Comprehensive income [abstract]
Profit (loss)	– GBP	54,100,000 GBP	288,400,000 GBP	234,300,000 GBP	—	—	—	—	—	—	– GBP	– GBP	200,000 GBP	– GBP	234,500,000 GBP	—	—	– GBP	– GBP	—	– GBP	—	—	– GBP	– GBP	200,000 GBP	– GBP	244,400,000 GBP	– GBP	– GBP	– GBP	—	—	– GBP	—	—	—	—	—	244,200,000 GBP	—	247,900,000 GBP	3,700,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Other comprehensive income	– GBP	—	—	44,600,000 GBP	—	—	—	—	—	—	45,200,000 GBP	– GBP	100,000 GBP	– GBP	7,600,000 GBP	—	—	1,000,000 GBP	6,100,000 GBP	—	– GBP	—	—	– GBP	– GBP	– GBP	43,900,000 GBP	32,000,000 GBP	1,700,000 GBP	– GBP	1,100,000 GBP	—	—	– GBP	—	—	—	—	—	73,100,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Comprehensive income	– GBP	—	—	278,900,000 GBP	—	—	—	—	—	—	45,200,000 GBP	– GBP	300,000 GBP	– GBP	226,900,000 GBP	—	—	1,000,000 GBP	6,100,000 GBP	—	– GBP	—	—	– GBP	– GBP	200,000 GBP	43,900,000 GBP	276,400,000 GBP	1,700,000 GBP	– GBP	1,100,000 GBP	—	—	– GBP	—	—	—	—	—	317,300,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Dividends recognised as distributions to owners	– GBP	—	—	73,300,000 GBP	—	—	—	—	—	—	– GBP	– GBP	– GBP	– GBP	73,300,000 GBP	—	—	– GBP	– GBP	—	– GBP	—	—	– GBP	– GBP	– GBP	– GBP	68,700,000 GBP	– GBP	– GBP	– GBP	—	—	– GBP	—	—	—	—	—	68,700,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Increase (decrease) through share-based payment transactions, equity	– GBP	—	—	17,700,000 GBP	—	—	—	—	—	—	– GBP	– GBP	– GBP	– GBP	17,700,000 GBP	—	—	– GBP	– GBP	—	– GBP	—	—	– GBP	– GBP	– GBP	– GBP	12,200,000 GBP	– GBP	– GBP	– GBP	—	—	– GBP	—	—	—	—	—	12,200,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—