Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 20, 2015
Entity Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Trading Symbol	ACE
Entity Registrant Name	ACE Ltd
Entity Central Index Key	0000896159
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		323,805,010