STOCKHOLDERS' EQUITY Part 2 AOCI (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Translation Adjustment	$ (280)		$ (280)		$ (293)	$ (264)
Change in cumulative translation adjustment	2	$ (20)	13	$ (15)	(29)
Benefit Plans Unrecognized Prior Service Credits	66		66		87	106
Change in Benefit Plans Unrecognized Prior Service Credits			(21)		(19)
Unrealized Gains (Losses) on Derivative Instruments	30		30		(66)	(55)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax			96		(11)
Unrealized Losses on Investments	(1)		(1)		(1)	(1)
Change in Unrealized Losses on Investments			0		0
Accumulated Other Comprehensive Income (Loss), Net of Tax	(185)		(185)		(273)	$ (214)
Total other comprehensive income (loss), net of tax	$ 48	$ (34)	$ 88	$ (29)	$ (59)

Amount, after tax, of accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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