BENEFITS PAYABLE - Schedule of Activity in Benefits Payable (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balances, beginning of period	$ 10,440	$ 10,241
Dispositions	(1)	0
Incurred related to:
Current year	83,004	75,976
Prior years	(913)	(693)
Total incurred	82,091	75,283
Paid related to:
Current year	(73,460)	(65,282)
Prior years	(8,982)	(9,117)
Total paid	(82,442)	(74,399)
Balances, end of period	$ 10,088	$ 11,125