Document and Entity Information	3 Months Ended
	Mar. 31, 2012	May 02, 2012
Document And Entity Information [Abstract]
Entity Registrant Name	EDISON MISSION ENERGY
Entity Central Index Key	0000930835
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		100