Amount of gain (loss) from excluded component of derivative hedge, recognized in earnings. Excludes recognition under systematic and rational method.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Financial Assets and Liabilities - Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative instruments in cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Earnings and Other Comprehensive Income - Recognized in OCI	$ 3		$ 3
Gain (Loss) Recognized in Earnings and Other Comprehensive Income - Reclassified from AOCI	6	$ 3	1	$ 17
Gain (Loss) Recognized in Earnings and Other Comprehensive Income - Amounts Excluded from Effectiveness Testing	0	0	0	0
Not designated as hedging instruments - economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (loss) from derivatives	1		1
Cost of services. \| Derivative instruments in cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Earnings and Other Comprehensive Income - Reclassified from AOCI	2	3	11	5
Cost of services. \| Foreign exchange contracts \| Derivative instruments in cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Earnings and Other Comprehensive Income - Recognized in OCI	3		3
Selling, general and administrative expense \| Derivative instruments in cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Earnings and Other Comprehensive Income - Reclassified from AOCI		(2)	(6)	2
Other (income) and expense \| Derivative instruments in cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Earnings and Other Comprehensive Income - Reclassified from AOCI	4	$ 1	(4)	$ 10
Other (income) and expense \| Foreign exchange contracts \| Not designated as hedging instruments - economic hedges
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (loss) from derivatives	$ 1		$ 1