FINANCIAL ASSETS AND LIABILITIES - Effect of Hedge Activity on Income and Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Cost of services	$ 3,824	$ 4,318
Selling, general and administrative expenses	690	714
Other expenses	27	$ 22
Cost of services.
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) from Hedge Activity	1
Other expenses
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) from Hedge Activity	$ (1)