GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Goodwill, balance at beginning of year	$ 6,563	$ 6,335
Goodwill acquired during the year	43	228	$ 335
Adjustments to goodwill	13	0
Goodwill, balance at end of year	6,619	6,563	$ 6,335
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Intangible assets, gross excluding goodwill	1,820	1,812
Accumulated amortization, intangible assets	(699)	(605)
Total intangible assets, net	1,121	1,207
Future amortization expense, 2020	96
Future amortization expense, 2021	90
Future amortization expense, 2022	87
Future amortization expense, 2023	85
Future amortization expense, 2024	82
Future amortization expense, thereafter	445
Future amortization expense, total	885
Intangible Assets Not Subject to Amortization - Tradenames
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Intangible assets, gross excluding goodwill	235	235
Total intangible assets, net	235	235
Intangible Assets Not Subject to Amortization - Other
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Intangible assets, gross excluding goodwill	1	1
Total intangible assets, net	$ 1	1
Customer Relationships
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted average amortization period	18 years
Intangible assets, gross excluding goodwill	$ 1,367	1,355
Accumulated amortization, intangible assets	(556)	(478)
Total intangible assets, net	$ 811	877
Non-compete Agreements
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted average amortization period	9 years
Intangible assets, gross excluding goodwill	$ 3	3
Accumulated amortization, intangible assets	(2)	(2)
Total intangible assets, net	$ 1	1
Technology
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted average amortization period	17 years
Intangible assets, gross excluding goodwill	$ 104	104
Accumulated amortization, intangible assets	(56)	(50)
Total intangible assets, net	$ 48	54
Other Intangible Assets, Subject To Amortization
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted average amortization period	9 years
Intangible assets, gross excluding goodwill	$ 110	114
Accumulated amortization, intangible assets	(85)	(75)
Total intangible assets, net	$ 25	39
Total Amortizing Intangible Assets
Finite-Lived and Indefinite-lived Intangible Assets [Line Items]
Weighted average amortization period	17 years
Intangible assets, gross excluding goodwill	$ 1,584	1,576
Accumulated amortization, intangible assets	(699)	(605)
Total intangible assets, net	$ 885	$ 971