INVESTMENTS - Total Investments in Bank and Financial Institution Sector, Including those Classified as Perpetual Securities (Detail) (Banks/financial Institutions, USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Summary of Investment Holdings [Line Items]
Amortized Cost	$ 20,196	$ 26,578
Fair Value	20,575	25,011
Percentage of Total Investment Portfolio, Amortized Cost	18.00%	27.00%
Percentage of Total Investment Portfolio, Fair Value	18.00%	25.00%
Fixed maturities
Summary of Investment Holdings [Line Items]
Amortized Cost	16,292	20,025
Fair Value	16,625	18,933
Percentage of Total Investment Portfolio, Amortized Cost	14.00%	20.00%
Percentage of Total Investment Portfolio, Fair Value	14.00%	19.00%
Perpetual securities | Upper Tier II
Summary of Investment Holdings [Line Items]
Amortized Cost	2,825	4,285
Fair Value	2,919	4,244
Percentage of Total Investment Portfolio, Amortized Cost	3.00%	5.00%
Percentage of Total Investment Portfolio, Fair Value	3.00%	4.00%
Perpetual securities | Tier I
Summary of Investment Holdings [Line Items]
Amortized Cost	1,079	2,268
Fair Value	$ 1,031	$ 1,834
Percentage of Total Investment Portfolio, Amortized Cost	1.00%	2.00%
Percentage of Total Investment Portfolio, Fair Value	1.00%	2.00%