Statement Of Changes In Equity [Abstract]

Babcock International Group PLC - Filing #1912722

Concept	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	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	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	As at 2023-03-31	2022-04-01 to 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	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	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	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	2021-04-01 to 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	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	—	—	353,900,000 GBP	3,000,000 GBP	768,800,000 GBP	—	—	370,900,000 GBP	873,000,000 GBP	303,400,000 GBP	30,600,000 GBP	—	—	—	—	—	17,000,000 GBP	1,568,800,000 GBP	56,100,000 GBP	—	30,600,000 GBP	—	—	—	—	—	—	682,000,000 GBP	768,800,000 GBP	4,000,000 GBP	303,400,000 GBP	56,400,000 GBP	873,000,000 GBP	1,241,400,000 GBP	—	19,500,000 GBP	701,500,000 GBP	—	—	—	30,600,000 GBP	1,671,700,000 GBP	229,000,000 GBP	303,400,000 GBP	873,000,000 GBP	16,000,000 GBP	213,000,000 GBP	48,400,000 GBP	768,800,000 GBP	42,700,000 GBP
Changes in equity [abstract]
Comprehensive income [abstract]
Profit (loss)	– GBP	35,000,000 GBP	—	—	—	– GBP	– GBP	—	—	—	—	– GBP	– GBP	– GBP	1,700,000 GBP	35,000,000 GBP	—	—	—	33,300,000 GBP	—	164,200,000 GBP	– GBP	3,700,000 GBP	– GBP	164,200,000 GBP	– GBP	—	—	—	—	—	—	—	167,900,000 GBP	—	—	– GBP	– GBP	– GBP	—	—	—	—	—	—	—	—	—	—
Other comprehensive income	– GBP	302,300,000 GBP	—	—	—	– GBP	1,000,000 GBP	—	—	—	—	300,000 GBP	– GBP	– GBP	2,000,000 GBP	301,600,000 GBP	—	—	—	304,300,000 GBP	—	297,000,000 GBP	– GBP	900,000 GBP	8,000,000 GBP	258,300,000 GBP	– GBP	—	—	—	—	—	—	—	297,900,000 GBP	—	—	– GBP	46,700,000 GBP	– GBP	—	—	—	—	—	—	—	—	—	—
Comprehensive income	– GBP	337,300,000 GBP	—	—	—	– GBP	1,000,000 GBP	—	—	—	—	300,000 GBP	– GBP	– GBP	300,000 GBP	336,600,000 GBP	—	—	—	337,600,000 GBP	—	461,200,000 GBP	– GBP	4,600,000 GBP	8,000,000 GBP	422,500,000 GBP	– GBP	—	—	—	—	—	—	—	465,800,000 GBP	—	—	– GBP	46,700,000 GBP	– GBP	—	—	—	—	—	—	—	—	—	—
Dividends recognised as distributions to owners	– GBP	– GBP	—	—	—	– GBP	– GBP	—	—	—	—	– GBP	– GBP	– GBP	2,200,000 GBP	– GBP	—	—	—	2,200,000 GBP	—	– GBP	– GBP	1,100,000 GBP	– GBP	– GBP	– GBP	—	—	—	—	—	—	—	1,100,000 GBP	—	—	– GBP	– GBP	– GBP	—	—	—	—	—	—	—	—	—	—
Increase (decrease) through share-based payment transactions, equity	– GBP	9,400,000 GBP	—	—	—	– GBP	– GBP	—	—	—	—	– GBP	– GBP	– GBP	– GBP	9,400,000 GBP	—	—	—	9,400,000 GBP	—	5,500,000 GBP	– GBP	– GBP	– GBP	5,500,000 GBP	– GBP	—	—	—	—	—	—	—	5,500,000 GBP	—	—	– GBP	– GBP	– GBP	—	—	—	—	—	—	—	—	—	—
Increase (decrease) in equity	– GBP	328,100,000 GBP	—	—	—	– GBP	1,000,000 GBP	—	—	—	—	300,000 GBP	– GBP	– GBP	2,500,000 GBP	327,400,000 GBP	—	—	—	330,600,000 GBP	—	469,000,000 GBP	– GBP	3,500,000 GBP	8,000,000 GBP	430,300,000 GBP	– GBP	—	—	—	—	—	—	—	472,500,000 GBP	—	—	– GBP	46,700,000 GBP	– GBP	—	—	—	—	—	—	—	—	—	—