Document and Entity Information - SFr / shares	9 Months Ended
	Sep. 30, 2018	Oct. 18, 2018	Dec. 31, 2017
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, 2018
Document Fiscal Year Focus	2018
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
Entity Small Business	false
Entity Emerging Growth Company	false
Common Shares Outstanding		460,805,372