Segment Information - Non-insurance Revenue from Customers (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Insurance Commissions and Fees	$ 333	$ 319
Other revenues	19	20
Non-insurance revenues with customers	352	338
Installment billing fees [Member] | Operating Segments [Member] | Commercial Lines
Segment Reporting Information [Line Items]
Insurance Commissions and Fees	11	10
Installment billing fees [Member] | Operating Segments [Member] | Personal Lines
Segment Reporting Information [Line Items]
Insurance Commissions and Fees	8	8
Insurance servicing revenues | Operating Segments [Member] | Personal Lines
Segment Reporting Information [Line Items]
Other revenues	19	19
Administrative services | Operating Segments [Member] | Group Benefits
Segment Reporting Information [Line Items]
Insurance Commissions and Fees	54	51
Advisor, distribution and other management fees | Operating Segments [Member] | Hartford Funds
Segment Reporting Information [Line Items]
Insurance Commissions and Fees	250	241
Investment management and other fees | Corporate
Segment Reporting Information [Line Items]
Insurance Commissions and Fees	$ 10	$ 9