Segment Information - Net Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Net income	$ 535	$ 443
Preferred stock dividends	5	5
Net income available to common stockholders	530	438
Corporate
Segment Reporting Information [Line Items]
Net income	(24)	(59)
Commercial Lines | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income	421	383
Personal Lines | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income	(1)	77
Property & Casualty Other Operations | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income	6	8
Group Benefits | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income	92	(8)
Hartford Funds | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net income	$ 41	$ 42