Segments - Pre-Tax Income Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Pre-tax income from continuing operations
Amortization of acquired intangible assets	$ (414)	$ (417)	$ (1,194)	$ (1,337)
Acquisition-related (charges)/income	(25)	(1)	(35)	(9)
Non-operating retirement-related (costs)/income	12	(6,062)	16	(6,455)
Kyndryl-related impacts	0	14	0	(353)
Workforce rebalancing charges	(34)	0	(410)	0
Other divested businesses	8	0	4	108
Total pre-tax income/(loss) from continuing operations	1,873	(4,501)	4,931	(2,156)
Operating Segments
Pre-tax income from continuing operations
Workforce rebalancing charges		(13)		(22)
Total pre-tax income/(loss) from continuing operations	2,473	2,128	6,983	6,470
Unallocated corporate amounts and other
Pre-tax income from continuing operations
Total pre-tax income/(loss) from continuing operations	$ (148)	$ (163)	$ (432)	$ (581)