INVESTMENTS - Components of Net Investment Income (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income									$ 3,230	$ 3,399	$ 3,371
Less investment expenses									95	80	78
Net investment income	$ 792	$ 784	$ 777	$ 782	$ 808	$ 841	$ 843	$ 827	3,135	3,319	3,293
Fixed maturities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income									3,094	3,249	3,210
Perpetual securities
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income									114	141	153
Equity securities and other
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income									18	7	7
Short term investments and cash equivalents
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income									$ 4	$ 2	$ 1