Statement Of Comprehensive Income [Abstract]

Direct Line Insurance Group PLC - Filing #3490597

Concept	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2021-01-01 to 2021-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31	2020-01-01 to 2020-12-31
Statement of comprehensive income [abstract]
Profit (loss)	— GBP	— GBP	— GBP	— GBP	— GBP	343,700,000 GBP	— GBP	343,700,000 GBP	343,700,000 GBP	367,200,000 GBP	— GBP	— GBP	367,200,000 GBP	— GBP	— GBP	367,200,000 GBP	— GBP	— GBP
Other comprehensive income [abstract]
Components of other comprehensive income that will not be reclassified to profit or loss, before tax [abstract]
Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans	—	—	—	—	—	—	—	3,800,000 GBP	—	—	—	—	400,000 GBP	—	—	—	—	—
Components of other comprehensive income that will be reclassified to profit or loss, before tax [abstract]
Cash flow hedges [abstract]
Gains (losses) on cash flow hedges, before tax	—	—	—	—	—	—	—	300,000 GBP	—	—	—	—	100,000 GBP	—	—	—	—	—
Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract]
Income tax relating to remeasurements of defined benefit plans included in other comprehensive income	—	—	—	—	—	—	—	800,000 GBP	—	—	—	—	300,000 GBP	—	—	—	—	—
Income tax relating to components of other comprehensive income that will be reclassified to profit or loss [abstract]
Income tax relating to components of other comprehensive income that will be reclassified to profit or loss	—	—	—	—	—	—	—	17,100,000 GBP	—	—	—	—	9,900,000 GBP	—	—	—	—	—
Other comprehensive income	74,900,000 GBP	— GBP	— GBP	— GBP	300,000 GBP	72,200,000 GBP	— GBP	72,200,000 GBP	3,000,000 GBP	100,000 GBP	— GBP	— GBP	36,200,000 GBP	36,400,000 GBP	100,000 GBP	36,200,000 GBP	— GBP	— GBP
Comprehensive income	74,900,000 GBP	— GBP	— GBP	— GBP	300,000 GBP	271,500,000 GBP	— GBP	271,500,000 GBP	346,700,000 GBP	367,100,000 GBP	— GBP	— GBP	403,400,000 GBP	36,400,000 GBP	100,000 GBP	403,400,000 GBP	— GBP	— GBP
Comprehensive income attributable to [abstract]
Comprehensive income, attributable to owners of parent	—	—	—	—	—	—	—	271,500,000 GBP	—	—	—	—	403,400,000 GBP	—	—	—	—	—