Segment Information - Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Income tax expense	$ 584	$ 443	$ 534
Operating Segments | P&C Commercial Lines
Segment Reporting Information [Line Items]
Income tax expense	502	426	402
Operating Segments | P&C Personal Lines
Segment Reporting Information [Line Items]
Income tax expense	(15)	22	95
Operating Segments | Property & Casualty Other Operations
Segment Reporting Information [Line Items]
Income tax expense	(36)	(52)	(28)
Operating Segments | Group Benefits [Member]
Segment Reporting Information [Line Items]
Income tax expense	133	75	56
Operating Segments | Hartford Funds
Segment Reporting Information [Line Items]
Income tax expense	45	41	56
Corporate
Segment Reporting Information [Line Items]
Income tax expense	$ (45)	$ (69)	$ (47)