BENEFITS PAYABLE - Schedule of Activity in Benefits Payable (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balances, beginning of period	$ 10,440	$ 10,241
Incurred related to:
Current year	27,012	25,659
Prior years	(477)	(535)
Total incurred	26,535	25,124
Paid related to:
Current year	(17,605)	(16,061)
Prior years	(7,919)	(7,575)
Total paid	(25,524)	(23,636)
Balances, end of period	$ 11,451	$ 11,729