SCHEDULE IV REINSURANCE (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Premiums earned
Net earned premiums	$ 1,987.3		$ 2,063.6		$ 1,924.5
OneBeacon
Premiums earned
Gross amount	1,043.3	[1]	1,158.3	[1]	1,035.9	[1]
Ceded to other companies	(71.4)	[1]	(79.1)	[1]	(66.0)	[1]
Assumed from other companies	148.5	[1]	52.8	[1]	42.3	[1]
Net earned premiums	1,120.4	[1]	1,132.0	[1]	1,012.2	[1]
Percentage of amount assumed to net	13.30%	[1]	4.70%	[1]	4.20%	[1]
Sirius Group
Premiums earned
Gross amount	174.0		169.9		128.5
Ceded to other companies	(246.2)		(226.6)		(206.0)
Assumed from other companies	938.6		988.3		989.8
Net earned premiums	$ 866.4		$ 931.6		$ 912.3
Percentage of amount assumed to net	108.30%		106.10%		108.50%

[1] The amounts shown excludes balances reclassified to held for sale in the consolidated balance sheets related to the Runoff Transaction as of December 31, 2013 and 2012 and to AutoOne as of December 31, 2011. See Note 21 - “Discontinued Operations”.