POLICY LIABILITIES - Changes in Liability for Unpaid Policy Claims (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Liability for Unpaid Claims and Claims Expenses
Net balance, beginning of period			$ 4,045
Less claims paid during the period on claims incurred during:
Net balance, end of period	$ 4,368		4,368
Total liability for unpaid policy claims	4,368	$ 4,346	4,368	$ 4,346
Health insurance
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of period	3,872	3,941	3,707	3,548
Less reinsurance recoverables	30	30	27	26
Net balance, beginning of period	3,842	3,911	3,680	3,522
Add claims incurred during the period related to:
Current year	1,759	1,843	5,278	5,309
Prior years	(126)	(148)	(386)	(374)
Total incurred	1,633	1,695	4,892	4,935
Less claims paid during the period on claims incurred during:
Current year	1,357	1,462	3,074	3,160
Prior years	234	232	1,697	1,722
Total paid	1,591	1,694	4,771	4,882
Effect of foreign exchange rate changes on unpaid claims	(14)	42	69	379
Net balance, end of period	3,870	3,954	3,870	3,954
Add reinsurance recoverables	30	31	30	31
Total liability for unpaid policy claims	3,900	3,985	3,900	3,985
Life insurance
Less claims paid during the period on claims incurred during:
Total liability for unpaid policy claims	$ 468	$ 361	$ 468	$ 361