Basis of Presentation and Significant Accounting Policies Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 03, 2018	Dec. 31, 2016
Income Taxes Paid	$ 21	$ 35	$ 40
AMPS Exchange Carrying Value of Surplus Notes Issued				$ 187
Decrease in long-term debt as a result of an exchange for investment securities			55
Non Cash Impact of Rehabilitation Exit Transaction		1,919
Cash and cash equivalents	24	63	624
Restricted Cash	55	19
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	81	83	625		$ 96
Long-term Debt [Member]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	143	232	39
Variable Interest Entity, Primary Beneficiary [Member]
Restricted Cash	$ 2	$ 1	$ 1