Analysis Of Income And Expense [Abstract]

Serco Group PLC - Filing #2006912

Concept	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	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	2023-01-01 to 2023-12-31	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	2022-01-01 to 2022-12-31	2022-01-01 to 2022-12-31
Analysis of income and expense [abstract]
Revenue [abstract]
Revenue	—	4,873,800,000 GBP	4,873,800,000 GBP	—	—	—	—	— GBP	—	—	—	—	4,534,000,000 GBP	—	—	—	— GBP	4,534,000,000 GBP
Material income and expense [abstract]
Investment income	—	7,000,000 GBP	7,000,000 GBP	—	—	—	—	— GBP	—	—	—	—	4,700,000 GBP	—	—	—	— GBP	4,700,000 GBP
Finance income (cost)	—	24,600,000 GBP	24,600,000 GBP	—	—	—	—	— GBP	—	—	—	—	20,400,000 GBP	—	—	—	— GBP	20,400,000 GBP
Expenses by nature [abstract]
Depreciation, amortisation and impairment loss (reversal of impairment loss) recognised in profit or loss [abstract]
Depreciation, amortisation and impairment loss (reversal of impairment loss) recognised in profit or loss	—	30,900,000 GBP	— GBP	—	—	—	—	30,900,000 GBP	—	—	—	—	21,600,000 GBP	—	—	—	21,600,000 GBP	— GBP
Miscellaneous other comprehensive income [abstract]
Other comprehensive income, net of tax, exchange differences on translation of foreign operations and hedges of net investments in foreign operations [abstract]
Other comprehensive income, net of tax, exchange differences on translation of foreign operations	—	38,400,000 GBP	—	—	—	—	—	—	—	—	—	—	60,200,000 GBP	—	—	—	—	—
Share of profit (loss) of associates and joint ventures accounted for using equity method [abstract]
Share of profit (loss) of associates and joint ventures accounted for using equity method	—	29,000,000 GBP	29,000,000 GBP	—	—	—	—	— GBP	—	—	—	—	12,000,000 GBP	—	—	—	— GBP	12,000,000 GBP
Share of other comprehensive income of associates and joint ventures accounted for using equity method, before tax [abstract]
Share of other comprehensive income of associates and joint ventures accounted for using equity method that will not be reclassified to profit or loss, before tax	—	1,100,000 GBP	—	—	—	—	—	—	—	—	—	—	2,900,000 GBP	—	—	—	—	—
Income tax relating to components of other comprehensive income [abstract]
Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss	—	6,100,000 GBP	—	—	—	—	—	—	—	—	—	—	27,100,000 GBP	—	—	—	—	—
Income tax relating to components of other comprehensive income that will be reclassified to profit or loss	—	200,000 GBP	—	—	—	—	—	—	—	—	—	—	100,000 GBP	—	—	—	—	—
Comprehensive income, continuing and discontinued operations [abstract]
Comprehensive income	— GBP	138,500,000 GBP	—	100,000 GBP	203,400,000 GBP	— GBP	138,400,000 GBP	—	65,000,000 GBP	— GBP	139,800,000 GBP	18,300,000 GBP	139,600,000 GBP	— GBP	158,100,000 GBP	200,000 GBP	—	—
Comprehensive income attributable to owners of parent, continuing and discontinued operations [abstract]
Comprehensive income, attributable to owners of parent	—	138,400,000 GBP	—	—	—	—	—	—	—	—	—	—	139,800,000 GBP	—	—	—	—	—
Comprehensive income attributable to non-controlling interests, continuing and discontinued operations [abstract]
Comprehensive income, attributable to non-controlling interests	—	100,000 GBP	—	—	—	—	—	—	—	—	—	—	200,000 GBP	—	—	—	—	—