Transactions With Affliated Parties (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction
Payment for commissions	$ 8	$ 7	$ 7
Earned premiums	5,604	5,170	4,954
Affiliated Parties
Related Party Transaction
Earned premiums	$ 48	$ 45	$ 45