Segments - Pre-Tax Income Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021		Sep. 30, 2022	Sep. 30, 2021
Pre-tax income from continuing operations
Amortization of acquired intangible assets	$ (417.0)	$ (469.0)		$ (1,337.0)	$ (1,371.0)
Acquisition-related (charges)/income	(1.0)	(4.0)		(9.0)	(37.0)
Non-operating retirement-related (costs)/income	(6,062.0)	(318.0)		(6,455.0)	(967.0)
Kyndryl-related impacts	14.0			(353.0)
Other - divested businesses	0.0	(41.0)		108.0	(106.0)
Income/(loss) from continuing operations before income taxes	(4,501.0)	813.0	[1]	(2,156.0)	1,968.0	[1]
Pre-tax pension settlement charge	5,900.0			5,894.0
Business Segments
Pre-tax income from continuing operations
Income/(loss) from continuing operations before income taxes	2,128.0	1,797.0		6,470.0	5,071.0
Internal transactions
Pre-tax income from continuing operations
Income/(loss) from continuing operations before income taxes	0.0	1.0		(15.0)	(3.0)
Unallocated corporate amounts
Pre-tax income from continuing operations
Income/(loss) from continuing operations before income taxes	$ (163.0)	$ (155.0)		$ (565.0)	$ (619.0)

[1] Reclassified to reflect discontinued operations presentation.