Capital Contributions, Dividends and Statutory Information (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Dividends Payable [Line Items]
Percentage threshold of dividends paid in previous twelve months to earned statutory surplus of prior year end, requiring approval of payment of dividends if exceeded			10.00%
Capital contribution from parent			$ 20	$ 0	$ 57
Statutory net income (loss)	$ 299	$ 325	794
Statutory capital and surplus			2,200	2,000
Contribution of capital			318	$ 0	57
Parent Company
Dividends Payable [Line Items]
Dividends paid to parent company	$ 294		78		396
Capital contribution from parent					$ 57
Parent Company | CONNECTICUT
Dividends Payable [Line Items]
Dividends paid to parent company			$ 474