INVESTMENTS - Composition of Investments in Unrealized Loss Position in Bank and Financial Institution Sector (Detail) (Banks/financial Institutions)	Mar. 31, 2013	Dec. 31, 2012
Investments, Unrealized Loss Position [Line Items]
Percentage of Total Investments in an Unrealized Loss Position	33.00%	22.00%
Percentage of Total Unrealized Losses	55.00%	50.00%
Fixed Maturities
Investments, Unrealized Loss Position [Line Items]
Percentage of Total Investments in an Unrealized Loss Position	26.00%	18.00%
Percentage of Total Unrealized Losses	35.00%	39.00%
Perpetual Securities
Investments, Unrealized Loss Position [Line Items]
Percentage of Total Investments in an Unrealized Loss Position	7.00%	4.00%
Percentage of Total Unrealized Losses	20.00%	11.00%
Perpetual Securities | Upper Tier II
Investments, Unrealized Loss Position [Line Items]
Percentage of Total Investments in an Unrealized Loss Position	5.00%	2.00%
Percentage of Total Unrealized Losses	13.00%	4.00%
Perpetual Securities | Tier I
Investments, Unrealized Loss Position [Line Items]
Percentage of Total Investments in an Unrealized Loss Position	2.00%	2.00%
Percentage of Total Unrealized Losses	7.00%	7.00%