Condensed Unaudited Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2011

Condensed Unaudited Quarterly Financial Data [Abstract]

Schedule Of Condensed Unaudited Quarterly Financial Data

	Three Months Ended
(in millions of U.S. dollars, except per share data)	March 31 2011			June 30 2011			September 30 2011			December 31 2011
Net premiums earned	$	3,309		$	3,757		$	4,490		$	3,831
Net investment income		544			569			564			565
Net realized gains (losses) including OTTI		(45	)		(73	)		(760	)		83
Total revenues	$	3,808		$	4,253		$	4,294		$	4,479
Losses and loss expenses	$	2,263		$	2,226		$	2,745		$	2,286
Policy benefits	$	91		$	108		$	83		$	119
Net income (loss)	$	259		$	607		$	(31	)	$	750
Basic earnings per share	$	0.77		$	1.79		$	(0.09	)	$	2.22
Diluted earnings per share	$	0.76		$	1.77		$	(0.09	)	$	2.20
	Three Months Ended
(in millions of U.S. dollars, except per share data)	March 31 2010			June 30 2010			September 30 2010			December 31 2010
Net premiums earned	$	3,277		$	3,233		$	3,422		$	3,572
Net investment income		504			518			516			532
Net realized gains (losses) including OTTI		168			9			(50	)		305
Total revenues	$	3,949		$	3,760		$	3,888		$	4,409
Losses and loss expenses	$	1,921		$	1,800		$	1,887		$	1,971
Policy benefits	$	87		$	87		$	93		$	90
Net income	$	755		$	677		$	675		$	1,001
Basic earnings per share	$	2.23		$	1.99		$	1.98		$	2.94
Diluted earnings per share	$	2.22		$	1.98		$	1.97		$	2.92