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	Mar. 31, 2013	Dec. 31, 2012
Summary of Investment Holdings [Line Items]
Amortized Cost	$ 18,358	$ 20,196
Fair Value	17,839	20,575
Percentage of Total Investment Portfolio, Amortized Cost	18.00%	18.00%
Percentage of Total Investment Portfolio, Fair Value	17.00%	18.00%
Fixed Maturities
Summary of Investment Holdings [Line Items]
Amortized Cost	15,010	16,292
Fair Value	14,924	16,625
Percentage of Total Investment Portfolio, Amortized Cost	15.00%	14.00%
Percentage of Total Investment Portfolio, Fair Value	14.00%	14.00%
Perpetual Securities | Upper Tier II
Summary of Investment Holdings [Line Items]
Amortized Cost	2,340	2,825
Fair Value	2,059	2,919
Percentage of Total Investment Portfolio, Amortized Cost	2.00%	3.00%
Percentage of Total Investment Portfolio, Fair Value	2.00%	3.00%
Perpetual Securities | Tier I
Summary of Investment Holdings [Line Items]
Amortized Cost	1,008	1,079
Fair Value	$ 856	$ 1,031
Percentage of Total Investment Portfolio, Amortized Cost	1.00%	1.00%
Percentage of Total Investment Portfolio, Fair Value	1.00%	1.00%