Other (income) expense (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Income and Expenses [Abstract]
Equity in net (income) loss of partially-owned entities		$ (418)	$ (264)	$ (113)
(Gains) losses from fair value changes in separate account assets	[1]	(97)	(11)	19
One-time contribution to the Chubb Charitable Foundation		50	0	0
Federal excise and capital taxes		35	19	19
Other		30	34	24
Other (income) expense		$ (400)	$ (222)	$ (51)

[1] (1) Related to (gains) losses from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP.