SCHEDULE III SUPPLEMENTARY INSURANCE INFORMATION (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
SUPPLEMENTARY INSURANCE INFORMATION
Net investment income	$ 110.9		$ 153.6		$ 184.5
OneBeacon
SUPPLEMENTARY INSURANCE INFORMATION
Deferred acquisition costs	103.7	[1]	123.9	[1]	123.5	[1]
Future policy benefits, losses, claims and loss expenses	1,054.3	[1]	1,000.0	[1]	3,358.6	[1]
Unearned premiums	544.9	[1]	573.8	[1]	528.0	[1]
Other policy claims and benefits payable	0	[1]	0	[1]	0	[1]
Premiums earned	1,120.4	[1]	1,132.0	[1]	1,012.2	[1]
Net investment income	41.1	[1],[2]	53.6	[1],[2]	71.4	[1],[2]
Benefits, claims, losses, and settlement expenses	622.1	[1]	650.0	[1]	548.3	[1]
Amortization of deferred policy acquisition costs	208.9	[1]	249.4	[1]	221.2	[1]
Other operating expenses	204.8	[1]	205.2	[1]	162.3	[1]
Premiums written	1,088.6	[1]	1,179.2	[1]	1,062.7	[1]
Net investment income	41.1		53.6		71.4
Sirius Group
SUPPLEMENTARY INSURANCE INFORMATION
Deferred acquisition costs	69.3		71.4		63.5
Future policy benefits, losses, claims and loss expenses	2,025.0		2,168.9		2,343.7
Unearned premiums	343.3		350.2		319.0
Other policy claims and benefits payable	0		0		0
Premiums earned	866.4		931.6		912.3
Net investment income	30.3	[2]	65.0	[2]	89.9	[2]
Benefits, claims, losses, and settlement expenses	418.4		543.9		626.0
Amortization of deferred policy acquisition costs	166.5		180.8		181.0
Other operating expenses	126.1		116.4		105.8
Premiums written	876.6		947.7		915.7
HG Global-BAM
SUPPLEMENTARY INSURANCE INFORMATION
Deferred acquisition costs	1.7		0
Future policy benefits, losses, claims and loss expenses	0		0
Unearned premiums	13.2		0
Other policy claims and benefits payable	0		0
Premiums earned	0.5		0
Net investment income	5.7	[2]	2.2	[2]
Benefits, claims, losses, and settlement expenses	0		0
Amortization of deferred policy acquisition costs	1.5		0
Other operating expenses	0.4		0.2
Premiums written	13.6		0
Other Operations
SUPPLEMENTARY INSURANCE INFORMATION
Deferred acquisition costs	0		0		0
Future policy benefits, losses, claims and loss expenses	0		0		0
Unearned premiums	0		0		0
Other policy claims and benefits payable	0		0		0
Premiums earned	0		0		0
Net investment income	0.1	[2]	0.5	[2]	(0.1)	[2]
Benefits, claims, losses, and settlement expenses	0		0		0
Amortization of deferred policy acquisition costs	0		0		0
Other operating expenses	0		0		0
Premiums written	0		0		0
Net investment income	15.3		32.8		23.2
Non-insurance [Member] | Operating Segments
SUPPLEMENTARY INSURANCE INFORMATION
Net investment income	$ 33.7		$ 32.3		$ 23.3

[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”.

[2] The amounts shown exclude net investment income relating to non-insurance operations of $33.7, $32.3 and $23.3 for the twelve months ended December 31, 2013, 2012 and 2011, respectively.