Restructuring and Other Costs, Before Tax (Details) - Other Operating Income (Expense) [Member] - Hartford Next Program - USD ($) $ in Millions	3 Months Ended		9 Months Ended		15 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	$ 12	$ 87	$ 1	$ 87	$ 103
Restructuring and Related Cost, Expected Cost	133		133		133
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	15	78	24	78	49
Restructuring and Related Cost, Expected Cost	49		49		49
Information Technology
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	2	0	6	0	8
Restructuring and Related Cost, Expected Cost	24		24		24
Professional fees and other expenses
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	1	$ 9	17	$ 9	46
Restructuring and Related Cost, Expected Cost	$ 60		$ 60		$ 60