Revenue Recognition - Disaggregation of Revenue by Major Products and Service Offerings (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenue by Major Products/Service Offerings
Total Revenue	$ 14,968	$ 14,752	$ 45,199	$ 44,479
Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	14,900	14,582	44,985	43,988
Other
Revenue by Major Products/Service Offerings
Revenue	68	170	214	491
Software | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	6,524	5,947	19,162	17,832
Software | Hybrid Platform & Solutions | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	4,600	4,187	13,272	12,388
Software | Transaction Processing | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,925	1,759	5,889	5,444
Consulting | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	5,152	5,178	15,517	15,601
Consulting | Business Transformation | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	2,327	2,291	7,004	6,869
Consulting | Application Operations | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,921	1,944	5,761	5,924
Consulting | Technology Consulting | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	905	943	2,752	2,808
Infrastructure | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	3,042	3,272	9,764	9,988
Infrastructure | Hybrid Infrastructure | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,765	1,943	5,928	5,912
Infrastructure | Infrastructure Support | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,277	1,329	3,835	4,076
Financing | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	$ 181	$ 186	$ 543	$ 566