Consolidated Statements Of Cash Flows Consolidated Statements of Cash Flows Parenthetical (USD $) In Millions, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011
Payments To Fund Decommissioning Fund	$ 3.4	$ 6.4

The cash outflow related to funding the decommissioning trust fund.

No definition available.

Name:	ee_PaymentsToFundDecommissioningFund
Namespace Prefix:	ee_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration