GOODWILL AND OTHER INTANGIBLE ASSETS - Changes in Goodwill Balances (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Goodwill
Balance at beginning of period	$ 58,730
Acquisitions	0
Dispositions, currency exchange and other	(5,536)
Balance at end of period	53,194
Operating Segments | Power
Goodwill
Balance at beginning of period	1,772
Acquisitions	0
Dispositions, currency exchange and other	14
Balance at end of period	1,787
Operating Segments | Renewable Energy
Goodwill
Balance at beginning of period	3,971
Acquisitions	0
Dispositions, currency exchange and other	23
Balance at end of period	3,994
Operating Segments | Aviation
Goodwill
Balance at beginning of period	9,839
Acquisitions	0
Dispositions, currency exchange and other	2
Balance at end of period	9,841
Operating Segments | Oil & Gas
Goodwill
Balance at beginning of period	24,455
Acquisitions	0
Dispositions, currency exchange and other	60
Balance at end of period	24,514
Operating Segments | Healthcare
Goodwill
Balance at beginning of period	17,226
Acquisitions	0
Dispositions, currency exchange and other	(5,500)
Balance at end of period	11,727
Operating Segments | Capital
Goodwill
Balance at beginning of period	904
Acquisitions	0
Dispositions, currency exchange and other	(26)
Balance at end of period	878
Corporate
Goodwill
Balance at beginning of period	563
Acquisitions	0
Dispositions, currency exchange and other	(109)
Balance at end of period	$ 454