Regulatory Accounting (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Unrecognized Equity Return	$ 322
Amount Of Allowed Equity Return Recognized In Period	$ 7	$ 13

Represents the balance of the allowed return on equity that has been deferred and recorded on the balance sheet

No definition available.

Name:	cehe_UnrecognizedEquityReturn
Namespace Prefix:	cehe_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant