EQUITY METHOD INVESTMENT - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Purchase of equity method investment		$ 0	$ 1,095	$ 0
Equity method investment		1,063	1,047
Put option
Schedule of Equity Method Investments [Line Items]
Purchase price allocated to put options	$ 236
Call option
Schedule of Equity Method Investments [Line Items]
Purchase price allocated to call options	$ 291
Options
Schedule of Equity Method Investments [Line Items]
(Income) expense on put and call options		(506)	33
Other long-term liabilities | Put option
Schedule of Equity Method Investments [Line Items]
Fair value of financial liability		28	224
Other long-term assets | Call option
Schedule of Equity Method Investments [Line Items]
Fair value of financial asset		$ 557	$ 246
Kindred at Home
Schedule of Equity Method Investments [Line Items]
Equity method investment ownership (percent)	40.00%
Purchase of equity method investment	$ 1,100
Equity method investment	$ 1,000