Total amount of payments made during the reporting period to settle insured claims and pay costs incurred in the claims settlement process.

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Loss and Loss Adjustment Expense Reserves (Details) (USD $) In Millions	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended							3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 OneBeacon Segment	Sep. 30, 2010 OneBeacon Segment	Sep. 30, 2011 OneBeacon Segment	Sep. 30, 2010 OneBeacon Segment	Jun. 30, 2011 AutoOne	Dec. 31, 2010 AutoOne	Sep. 30, 2010 AutoOne	Jun. 30, 2010 AutoOne	Dec. 31, 2009 AutoOne	Sep. 30, 2011 Sirius Group.	Sep. 30, 2010 Sirius Group.	Sep. 30, 2011 Sirius Group.	Sep. 30, 2010 Sirius Group.
Loss and Loss Adjustment Expense Reserves
Gross beginning balance	$ 5,642.4	$ 6,198.1	$ 5,736.8	$ 6,379.2
Less beginning reinsurance recoverable on unpaid losses	(2,193.0)	(2,748.3)	(2,344.0)	(2,771.5)
Net loss and LAE reserves	3,449.4	3,449.8	3,392.8	3,607.7					58.6	81.7	82.9	68.2	95.8
Loss and LAE reserves acquired - Central National				17.6
Loss and LAE reserves sold - One Beacon Personal Lines				(231.0)
Loss and LAE incurred relating to Current year losses	307.8	284.7	972.2	1,244.9
Loss and LAE incurred relating to Prior year losses	(30.7)	(31.3)	(58.2)	(69.0)	(9.8)	(17.8)	(25.0)	(42.1)						(20.9)	(13.5)	(33.2)	(26.9)
Total incurred losses and LAE	277.1	253.4	914.0	1,175.9										130.5	98.2	499.1	456.6
Accretion of fair value adjustment to loss and LAE reserves	2.1	2.1	6.2	6.3
Foreign currency translation adjustment to loss and LAE reserves	(25.5)	39.9	5.7	6.7
Loss and LAE paid relating to Current year losses	(112.8)	(156.3)	(237.9)	(403.9)
Loss and LAE paid relating to Prior year losses	(230.9)	(211.8)	(711.8)	(788.1)
Total loss and LAE payments	(343.7)	(368.1)	(949.7)	(1,192.0)
Net ending balance	3,300.8	3,378.3	3,300.8	3,378.3					58.6	81.7	82.9	68.2	95.8
Plus ending reinsurance recoverable on unpaid losses	(2,581.2)	(2,592.1)	(2,581.2)	(2,592.1)										(342.1)		(342.1)
Gross ending balance	5,882.0	5,970.4	5,882.0	5,970.4
Net favorable loss reserve development	30.7	31.3	58.2	69.0	9.8	17.8	25.0	42.1						20.9	13.5	33.2	26.9
Pre-tax un-accreted adjustment			$ 14.9