Accrued Restructuring and Other Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 87	$ 0	$ 87	$ 0
Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(12)
Employee Severance | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(3)
Information Technology | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			0
Professional fees and other expenses | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Payments for Restructuring			(9)
Other Operating Income (Expense) [Member] | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			87
Other Operating Income (Expense) [Member] | Employee Severance | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			78
Other Operating Income (Expense) [Member] | Information Technology | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			0
Other Operating Income (Expense) [Member] | Professional fees and other expenses | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			9
Other liabilities | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance			0
Restructuring Reserve, Ending Balance	75		75
Other liabilities | Employee Severance | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance			0
Restructuring Reserve, Ending Balance	75		75
Other liabilities | Information Technology | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance			0
Restructuring Reserve, Ending Balance	0		0
Other liabilities | Professional fees and other expenses | Hartford Next Program
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Beginning Balance			0
Restructuring Reserve, Ending Balance	$ 0		$ 0