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INCOME TAXES - Changes in Liability for Tax Uncertainties, Excluding Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Liability for tax uncertainties	$ 8	$ 13
Changes in liability for tax uncertainties, excluding interest
Balance at beginning of year	37	45	$ 59
Additions for tax positions related to the current year	3	4	4
Additions for tax positions of prior years	1	3	5
Reductions for tax positions of prior years	(1)	(5)	(13)
Reductions due to statute lapse	(10)	(9)	(5)
Settlements, audit payments, refunds - net	(2)	(1)	(5)
Balance at end of year	$ 28	$ 37	$ 45

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Other information relative to a tax position which it is highly certain that the total amount of the unrecognized tax benefit will significantly increase or decrease but the timing of deductibility is uncertain.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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