Business and Basis of Presentation (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2019 subsidiary
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number Of Subsidiaries | subsidiary			1
Indirect subsidiary dissolved in December 31, 2018
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Number Of Subsidiaries | subsidiary			1
Net Realized Investments Gain Loss
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Out of Period Adjustment | $	$ 13
Income (loss) from operations before income taxes and equity in earnings of operating joint venture
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Out of Period Adjustment | $	$ (5)	$ 11