Unaudited Quarterly Financial Information (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

			2011												2010
(in millions of U.S. dollars,			Fourth			Third			Second			First			Fourth			Third			Second			First
except per share amounts)			Quarter			Quarter			Quarter			Quarter			Quarter			Quarter			Quarter			Quarter
Net premiums written		$		879.9	$		1,079.6	$		1,056.5	$		1,470.4	$		820.6	$		987.6	$		1,112.7	$		1,784.2
Net premiums earned				1,181.4			1,294.3			1,107.5			1,064.6			1,204.6			1,313.4			1,104.6			1,153.8
Net investment income				155.5			163.7			158.3			151.6			160.8			164.4			174.5			173.1
Net realized and unrealized
	investment gains (losses)			74.6			26.1			78.2			(112.2)			(83.2)			293.2			46.0			145.5
Other income				3.1			1.4			1.6			1.8			5.1			3.3			0.8			1.3
Total revenues				1,414.6			1,485.5			1,345.6			1,105.8			1,287.3			1,774.3			1,325.9			1,473.7
Losses and loss expenses
	and life policy benefits			1,069.2			881.7			814.5			1,607.2			817.8			748.9			704.6			1,012.4
Acquisition costs				238.8			262.5			229.2			207.9			246.6			261.6			244.1			220.1
Other operating expenses				113.0			103.8			113.7			104.3			133.2			118.2			160.2			128.1
Interest expense				12.3			12.2			12.2			12.3			12.2			12.3			12.8			7.1
Amortization of intangible assets				8.9			9.5			9.2			8.8			8.8			10.0			7.8			4.8
Net foreign exchange (gains) losses				(14.7)			(10.6)			(8.7)			(0.7)			8.3			27.1			(11.0)			(3.6)
Total expenses				1,427.5			1,259.1			1,170.1			1,939.8			1,226.9			1,178.1			1,118.5			1,368.9
(Loss) income before taxes and interest in
	(losses) earnings of equity investments			(12.9)			226.4			175.5			(834.0)			60.4			596.2			207.4			104.8
Income tax expense (benefit)				3.3			41.8			50.1			(26.3)			10.9			72.6			17.8			27.6
Interest in (losses) earnings of equity
	investments			(1.4)			(4.5)			(1.2)			0.7			7.5			1.3			1.3			2.4
Net (loss) income				(17.6)			180.1			124.2			(807.0)			57.0			524.9			190.9			79.6
Preferred dividends				15.4			14.4			8.6			8.6			8.6			8.6			8.6			8.6
Net (loss) income available to common
	shareholders	$		(33.0)	$		165.7	$		115.6	$		(815.6)	$		48.4	$		516.3	$		182.3	$		71.0
Basic net (loss) income per common share		$		(0.49)	$		2.45	$		1.71	$		(11.99)	$		0.66	$		6.86	$		2.36	$		0.87
Diluted net (loss) income per common share				(0.49)			2.43			1.69			(11.99)			0.65			6.76			2.31			0.85
Dividends declared per common share				0.60			0.60			0.60			0.55			0.55			0.50			0.50			0.50