Business and Basis of Presentation (Narrative) (Details) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 subsidiary
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Number Of Subsidiaries | subsidiary			1
Interest credited to policyholder account balances
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Out of Period Adjustment	$ 13
Realized investment gains (losses), net
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Out of Period Adjustment	13
Income (loss) from operations before income taxes and equity in earnings of operating joint venture
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Out of Period Adjustment	$ (5)	$ 11