Reinsurance - Effect on Premiums - Short-Duration Contracts (Details) - Short-duration contracts $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)
Written premiums
Direct	$ 864
Ceded	(23)
Net written premiums	841
Earned premiums
Direct	841
Ceded	(24)
Net premiums	$ 817

Amount of earned premiums ceded to other entities.

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