COMMITMENTS AND CONTINGENCIES (Detail) - Percentage Of Consolidated Gross Written Premiums	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
AON Corporation and Subsidiares [Member]
Percentage of gross premium written from property and casualty operations	20.00%	21.00%	20.00%
Marsh and McLennan Companies [Member]
Percentage of gross premium written from property and casualty operations	20.00%	21.00%	18.00%
The Willis Group [Member]
Percentage of gross premium written from property and casualty operations	12.00%	11.00%	9.00%