Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended	63 Months Ended
	Mar. 31, 2022	Dec. 31, 2016	Mar. 31, 2022
Loss Contingencies [Line Items]
Liability for unpaid losses and loss adjustment expenses, at undiscounted amounts	$ 519		$ 519
Asbestos and Environmental
Loss Contingencies [Line Items]
Reinsurance Retention Policy, Amount Retained		$ 1,700
Asbestos and Environmental
Loss Contingencies [Line Items]
Liability for unpaid losses and loss adjustment expenses, at undiscounted amounts	519		519
Asbestos and Environmental | Asbestos and Environmental
Loss Contingencies [Line Items]
Change in Deferred Gain on Retroactive Reinsurance	365		365
Reinsurance Retention Policy, Excess Retention, Amount Reinsured			$ 1,015
Asbestos and Environmental | Asbestos and Environmental | Remaining [Member]
Loss Contingencies [Line Items]
Maximum adverse loss development to be ceded under agreement	$ 485