INVESTMENTS - Information Regarding Changes in Unrealized Gains and Losses from Investments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Changes in unrealized gains (losses):
Changes in unrealized gains (losses)	$ 1,728	$ 2,799	$ (2,595)
Fixed maturities | Available-for-sale securities
Changes in unrealized gains (losses):
Changes in unrealized gains (losses)	1,457	2,690	(2,481)
Perpetual securities | Available-for-sale securities
Changes in unrealized gains (losses):
Changes in unrealized gains (losses)	200	21	(123)
Equity securities
Changes in unrealized gains (losses):
Changes in unrealized gains (losses)	$ 71	$ 88	$ 9