RELATED PARTIES - Narrative (Details) - USD ($)	3 Months Ended			6 Months Ended		9 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Impairment charge on minority-owned joint venture investments				$ 72,000,000		$ 0
UTC Net Investment
Related Party Transaction [Line Items]
Net contribution to parent	$ 859,000,000			780,000,000
Net cash contribution to parent				590,000,000
Spinoff
Related Party Transaction [Line Items]
Separation costs	23,000,000		$ 0	68,000,000	$ 0
Equity Method Investee
Related Party Transaction [Line Items]
Revenue from related parties	434,000,000		546,000,000	778,000,000	940,000,000
Related parties amount in cost of sales	66,000,000		101,000,000	143,000,000	178,000,000
Accounts receivable, related parties	219,000,000			219,000,000			$ 137,000,000
Impairment charge on minority-owned joint venture investments	0	$ 71,000,000
Accounts payable, related parties	38,000,000			38,000,000			55,000,000
UTC
Related Party Transaction [Line Items]
Revenue from related parties	0		6,000,000	3,000,000	12,000,000
Accounts receivable, related parties							16,000,000,000.0
Related party transaction, selling, general and administrative expenses from transactions with related party	0		62,000,000	43,000,000	116,000,000
Accounts payable, related parties							3,300,000,000
Interest income, related party	0		21,000,000	0	49,000,000
Interest expense, related party	0		$ 16,000,000	0	$ 32,000,000
Accounts receivable, related parties, current	0			0			6,000,000
Accounts payable, related parties, current	$ 0			$ 0			$ 4,000,000