REDEEMABLE NONCONTROLLING INTERESTS IN EQUITY OF CONSOLIDATED SUBSIDIARIES - Segment Details (Details) - Redeemable noncontrolling interests - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
REDEEMABLE NONCONTROLLING INTEREST
Redeemable noncontrolling interests	$ 1,526	$ 1,439	$ 1,506	$ 1,420
Net income available to redeemable noncontrolling interests	34	47
Hospital Operations
REDEEMABLE NONCONTROLLING INTEREST
Redeemable noncontrolling interests	380		383
Net income available to redeemable noncontrolling interests	(9)	(6)
Ambulatory Care
REDEEMABLE NONCONTROLLING INTEREST
Redeemable noncontrolling interests	784		777
Net income available to redeemable noncontrolling interests	27	33
Conifer
REDEEMABLE NONCONTROLLING INTEREST
Redeemable noncontrolling interests	362		$ 346
Net income available to redeemable noncontrolling interests	$ 16	$ 20