POLICY LIABILITIES - Changes in Liability for Unpaid Policy Claims (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of year	$ 4,392	$ 4,045
Net balance, beginning of year	4,392
Less claims paid during the year on claims incurred during:
Net balance, end of year	4,584	4,392
Total liability for unpaid policy claims	4,584	4,392	$ 4,045
Health insurance
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of year	3,884	3,707	3,548
Less reinsurance recoverables	30	27	26
Net balance, beginning of year	3,854	3,680	3,522
Add claims incurred during the year related to:
Current year	7,101	6,979	7,037
Prior years	(563)	(518)	(465)
Total incurred	6,538	6,461	6,572
Less claims paid during the year on claims incurred during:
Current year	4,612	4,530	4,613
Prior years	1,898	1,822	1,865
Total paid	6,510	6,352	6,478
Effect of foreign exchange rate changes on unpaid claims	43	65	64
Net balance, end of year	3,925	3,854	3,680
Add reinsurance recoverables	27	30	27
Total liability for unpaid policy claims	3,952	3,884	3,707
Life insurance
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of year	508	338
Less claims paid during the year on claims incurred during:
Total liability for unpaid policy claims	$ 632	$ 508	$ 338