Document And Entity Information (USD $)	6 Months Ended
	Jun. 30, 2011	Jul. 29, 2011	Jun. 30, 2010
Entity Registrant Name	EAST WEST BANCORP INC
Entity Central Index Key	0001069157
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	No
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 2,234,825,997
Entity Common Stock, Shares Outstanding		148,918,258
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2011