Statement Of Changes In Equity [Abstract]

Serco Group PLC - Filing #2006913

Concept	2023-01-01 to 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	2023-01-01 to 2023-12-31	2023-01-01 to 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	As at 2023-12-31	2023-01-01 to 2023-12-31	As at 2023-12-31	As at 2023-12-31	As at 2022-12-31	2022-01-01 to 2022-12-31	2022-01-01 to 2022-12-31	2022-01-01 to 2022-12-31	2022-01-01 to 2022-12-31	2022-01-01 to 2022-12-31	2022-01-01 to 2022-12-31	2022-01-01 to 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	2022-01-01 to 2022-12-31	2022-01-01 to 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
Statement of changes in equity [abstract]
Statement of changes in equity [line items]
Equity	—	1,033,700,000 GBP	—	—	—	—	659,100,000 GBP	—	110,300,000 GBP	—	—	300,000 GBP	463,100,000 GBP	—	22,100,000 GBP	1,034,000,000 GBP	1,029,700,000 GBP	—	—	—	—	—	—	—	129,900,000 GBP	1,500,000 GBP	463,100,000 GBP	670,600,000 GBP	24,400,000 GBP	1,028,200,000 GBP	—	—	542,800,000 GBP	23,600,000 GBP	1,006,700,000 GBP	463,100,000 GBP	1,700,000 GBP	24,400,000 GBP
Changes in equity [abstract]
Comprehensive income [abstract]
Profit (loss)	202,400,000 GBP	—	—	29,100,000 GBP	173,300,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	155,000,000 GBP	—	—	168,700,000 GBP	13,700,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Other comprehensive income	63,900,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	15,400,000 GBP	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
Comprehensive income	138,500,000 GBP	—	138,400,000 GBP	—	—	65,000,000 GBP	—	100,000 GBP	—	203,400,000 GBP	— GBP	—	—	— GBP	—	—	—	— GBP	18,300,000 GBP	139,600,000 GBP	158,100,000 GBP	200,000 GBP	—	—	—	—	—	—	—	—	139,800,000 GBP	— GBP	—	—	—	—	—	—
Dividends recognised as distributions to owners	—	—	33,700,000 GBP	—	—	— GBP	—	1,700,000 GBP	—	33,700,000 GBP	— GBP	—	—	— GBP	—	—	—	— GBP	— GBP	—	30,300,000 GBP	— GBP	—	—	—	—	—	—	—	—	30,300,000 GBP	— GBP	—	—	—	—	—	—
Increase (decrease) through treasury share transactions, equity	—	—	22,900,000 GBP	—	—	22,900,000 GBP	—	— GBP	—	— GBP	— GBP	—	—	— GBP	—	—	—	— GBP	15,900,000 GBP	—	— GBP	— GBP	—	—	—	—	—	—	—	—	15,900,000 GBP	— GBP	—	—	—	—	—	—
Increase (decrease) through share-based payment transactions, equity	—	—	13,500,000 GBP	—	—	13,500,000 GBP	—	— GBP	—	— GBP	— GBP	—	—	— GBP	—	—	—	— GBP	15,600,000 GBP	—	— GBP	— GBP	—	—	—	—	—	—	—	—	15,600,000 GBP	— GBP	—	—	—	—	—	—