Reinsurance Level 4 Reinsurance Revenue (Details) - Life Annuity Accident and Health Insurance Product Line [Member] - USD ($) $ in Millions	3 Months Ended		4 Months Ended	5 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	May 31, 2018	Sep. 30, 2017
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]
Gross Fee Income Earned Premium and Other Life	$ 616	$ 602	$ 817	$ 1,059	$ 1,837
Assumed Premiums Earned	29	30	39	48	89
Ceded Premiums Earned	421	390	554	684	1,168
Net Fee Income Earned Premium and Other Life	$ 224	$ 242	$ 302	$ 423	$ 758