POLICY LIABILITIES - Changes in Liability for Unpaid Policy Claims (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Liability for Unpaid Claims and Claims Expenses
Net balance, beginning of year	$ 4,045
Less claims paid during the year on claims incurred during:
Net balance, end of year	4,230
Total liability for unpaid policy claims	4,230	$ 3,990
Health insurance
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of year	3,707	3,548
Less reinsurance recoverables	27	26
Net balance, beginning of year	3,680	3,522
Add claims incurred during the year related to:
Current year	1,737	1,705
Prior years	(111)	(142)
Total incurred	1,626	1,563
Less claims paid during the year on claims incurred during:
Current year	505	493
Prior years	1,055	1,046
Total paid	1,560	1,539
Effect of foreign exchange rate changes on unpaid claims	80	136
Net balance, end of year	3,826	3,682
Add reinsurance recoverables	29	28
Total liability for unpaid policy claims	3,855	3,710
Life insurance
Less claims paid during the year on claims incurred during:
Total liability for unpaid policy claims	$ 375	$ 280