Reinsurance and Indemnification - Excess contract (Details) - USD ($) $ in Millions	7 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019
Reinsurance Retention Policy [Line Items]
Limit of aggregate losses under aggregate excess agreement		$ 3,400
Florida Excess Catastrophe Reinsurance Agreement
Reinsurance Retention Policy [Line Items]
Limit of aggregate losses under aggregate excess agreement	$ 54
Term of catastrophe reinsurance agreement contract		2 years
Florida Excess Catastrophe Reinsurance Agreement, Personal Property Lines
Reinsurance Retention Policy [Line Items]
Limit of aggregate losses under aggregate excess agreement		$ 249
Retention amount for catastrophe reinsurance agreement contracts		$ 20
Retention percentage of reinsurance limit		100.00%
Co-participation percentage		10.00%