Organization and Summary of Significant Accounting Policies (Schedule of Supplemental Disclosures of Cash Flow Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization and Summary of Significant Accounting Policies [Abstract]
Cash paid during the year for interest, net of amounts capitalized	$ 135	$ 130	$ 75
Cash paid (received) during the year for income taxes	6	(5)	(15)
Increase (decrease) in noncash property additions	$ (42)	$ 25	$ 55