TRANSITION PERIOD - Income Statement (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2022		Mar. 31, 2021	Mar. 31, 2024		Mar. 31, 2023		Dec. 31, 2021
TRANSITION PERIOD
Revenues	$ 4,431	[1]	$ 4,771	$ 16,052	[1]	$ 17,026	[1]	$ 18,657	[1]
Cost of services	3,824	[2]	4,318	13,189	[2]	14,498	[2]	16,550	[2]
Selling, general and administrative expenses	690		714	2,773		2,914		2,776
Workforce rebalancing charges			52	138		71		39
Transaction-related costs (benefits)	58		55	(46)		264		627
Interest expense	21		14	122		94		64
Other expense	27		22	45		35		35
Total costs and expenses	4,620		5,175	16,221		17,876		20,560
Income (loss) before income taxes	(189)		(403)	(168)		(851)		(1,903)
Provision for income taxes	40		91	172		524		402
Net income (loss)	$ (229)		$ (494)	$ (340)		$ (1,374)		$ (2,304)
NET LOSS PER SHARE
Basic earnings (loss) per share (in dollars per share)	$ (1.02)		$ (2.20)	$ (1.48)		$ (6.06)		$ (10.28)
Diluted earnings (loss) per share (in dollars per share)	$ (1.02)		$ (2.20)	$ (1.48)		$ (6.06)		$ (10.28)
Weighted-average basic shares outstanding (in shares)	224.4		224.1	229.2		226.7		224.1
Weighted-average diluted shares outstanding (in shares)	224.4		224.1	229.2		226.7		224.1

[1] Including related-party revenue of $287 for the year ended March 31, 2023, $236 for the three months ended March 31, 2022, and $704 for the year ended December 31, 2021

[2] Including related-party cost of service of $1,382 for the year ended March 31, 2023, $924 for the three months ended March 31, 2022, and $3,979 for the year ended December 31, 2021