GOODWILL AND INTANGIBLE ASSETS (Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Goodwill, Balance at beginning of period	$ 6,563	$ 6,335
Goodwill acquired during the period	42	228
Goodwill, Balance at end of period	$ 6,605	$ 6,563