Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Cash and Cash Equivalents, at Carrying Value	$ 1,491		$ 2,558
Interest Costs Capitalized	8		6		$ 2
Advertising Expense	76		61		55
Other operating costs	155	[1]	65	[1]	91	[2]
Receivables, net	457		494		$ 167
Variable Interest Entity, Primary Beneficiary [Member]
Cash and Cash Equivalents, at Carrying Value	$ 14		58
Adjustments for New Accounting Pronouncement [Member]
Receivables, net			(2)
Discontinued Operations, Disposed of by Means Other than Sale [Member]
Other operating costs			$ 19

[1] (2) Amounts include changes in fair value of the derivative liability related to the conversion option of the CEC Convertible Notes and the disputed claims liability as well as interest and dividend income.

[2] (3) Amounts primarily represent costs incurred in connection with development activities and reorganization activities, and/or recoveries associated with such items, including acquisition and integration costs, contract exit fees including exiting the fully bundled sales system of NV Energy for electric service at our Nevada properties, lease termination costs, gains and losses on asset sales, weather related property closure costs, demolition costs primarily at our Las Vegas properties for renovations, and project opening costs.