POLICY LIABILITIES - Changes in Liability for Unpaid Policy Claims (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Liability for Unpaid Claims and Claims Expenses
Net balance, beginning of period	$ 4,836
Less claims paid during the period on claims incurred during:
Net balance, end of period	4,754
Total liability for unpaid policy claims	4,754	$ 4,948
Health insurance
Liability for Unpaid Claims and Claims Expenses
Unpaid supplemental health claims, beginning of period	4,067	4,389
Less reinsurance recoverables	37	39
Net balance, beginning of period	4,030	4,350
Add claims incurred during the period related to:
Current year	1,737	1,859
Prior years	(208)	(320)
Total incurred	1,529	1,539
Less claims paid during the period on claims incurred during:
Current year	468	511
Prior years	987	1,061
Total paid	1,455	1,572
Effect of foreign exchange rate changes on unpaid claims	(135)	(162)
Net balance, end of period	3,969	4,155
Add reinsurance recoverables	40	37
Total liability for unpaid policy claims	4,009	4,192
Life insurance
Less claims paid during the period on claims incurred during:
Total liability for unpaid policy claims	$ 745	$ 756