Document and Entity Information	6 Months Ended
	Jun. 30, 2012	Jul. 31, 2012
Document and Entity Information
Entity Registrant Name	EAST WEST BANCORP INC
Entity Central Index Key	0001069157
Document Type	10-Q
Document Period End Date	Jun. 30, 2012
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		141,939,270
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q2