Document and Entity Information - SFr / shares	9 Months Ended
	Sep. 30, 2017	Oct. 20, 2017	Dec. 31, 2016
Entity Information [Line Items]
Common Shares, par value	SFr 24.15		SFr 24.15
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Trading Symbol	CB
Entity Registrant Name	Chubb Ltd
Entity Central Index Key	0000896159
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Common Shares Outstanding		464,221,986