Unpaid Losses and Loss Expenses and Policy Benefits for Life and Annuity Contracts (Tables)

12 Months Ended

Dec. 31, 2011

Disclosure - Unpaid Losses and Loss Expenses and Policy Benefits for Life and Annuity Contracts [Abstract]

Schedule Of Unpaid Losses And Loss Expenses By Type Table [Text Block]

		2011		2010
Case reserves	$	5,187,761	$	4,652,281
ACRs		495,593		326,721
IBNR reserves		5,589,737		5,687,602
Total unpaid losses and loss expenses	$	11,273,091	$	10,666,604

Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense [Text Block]

		2011		2010		2009
Gross liability at beginning of year	$	10,666,604	$	10,811,483	$	7,510,666
Reinsurance recoverable at beginning of year		348,747		336,352		125,215
Net liability at beginning of year		10,317,857		10,475,131		7,385,451
Net liability acquired related to Paris Re		—		—		3,176,255
Net incurred losses related to:
Current year		4,252,766		3,137,874		2,340,768
Prior years		(530,457)		(477,883)		(485,809)
		3,722,309		2,659,991		1,854,959
Change in Paris Re Reserve Agreement		(61,383)		(66,783)		(32,027)
Net paid losses related to:
Current year		930,407		311,253		327,080
Prior years		2,060,152		2,267,765		1,716,798
		2,990,559		2,579,018		2,043,878
Effects of foreign exchange rate changes		(68,238)		(171,464)		134,371
Net liability at end of year		10,919,986		10,317,857		10,475,131
Reinsurance recoverable at end of year		353,105		348,747		336,352
Gross liability at end of year	$	11,273,091	$	10,666,604	$	10,811,483

Reconciliation Of Loss And Loss Expenses Including Life Policy Benefits Table [Text Block]

		2011		2010		2009
Net incurred losses related to:
Non-life	$	3,722,309	$	2,659,991	$	1,854,959
Life		650,261		623,627		440,337
Losses and loss expenses and life policy benefits	$	4,372,570	$	3,283,618	$	2,295,296

Net Non Life Prior Year Loss Development Table [Text Block]

			2011		2010		2009
Prior year net favorable loss development:
Non-life sub-segment
	North America	$	189,180	$	165,780	$	177,571
	Global (Non-U.S.) P&C		115,995		97,539		151,456
	Global (Non-U.S.) Specialty		128,975		170,931		107,632
	Catastrophe		96,307		43,633		49,150
Total net Non-life prior year loss development		$	530,457	$	477,883	$	485,809