Segment Information - Non-insurance Revenue from Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Fee income	$ 1,300	$ 1,349	$ 1,488
Other Income	84	73	81
Revenue from Contract with Customer, Excluding Assessed Tax	1,382	1,423	1,569
Installment billing fees [Member] | Operating Segments | P&C Commercial Lines
Segment Reporting Information [Line Items]
Fee income	41	39	34
Installment billing fees [Member] | Operating Segments | P&C Personal Lines
Segment Reporting Information [Line Items]
Fee income	30	30	32
Insurance servicing fees [Member] | Operating Segments | P&C Personal Lines
Segment Reporting Information [Line Items]
Other Income	81	73	80
Administrative services fees [Member] | Operating Segments | Group Benefits [Member]
Segment Reporting Information [Line Items]
Fee income	217	187	183
Advisor, distribution and other management fees [Member] | Operating Segments | Hartford Funds
Segment Reporting Information [Line Items]
Fee income	973	1,044	1,189
Investment management and other fees [Member] | Corporate
Segment Reporting Information [Line Items]
Fee income	39	49	50
Other | Corporate
Segment Reporting Information [Line Items]
Other Income	$ 1	$ 1	$ 1