Revenue Recognition - Disaggregation of Revenue by Major Products and Service Offerings (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Revenue by Major Products/Service Offerings
Total Revenue	$ 15,917	$ 14,541
Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	15,870	14,480
Other
Revenue by Major Products/Service Offerings
Revenue	48	61
Software | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	7,052	6,336
Software | Hybrid Cloud | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,905	1,687
Software | Automation | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,741	1,584
Software | Data | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,474	1,236
Software | Transaction Processing | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,932	1,828
Consulting | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	5,272	5,068
Consulting | Strategy and Technology | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	2,896	2,782
Consulting | Intelligent Operations | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	2,376	2,286
Infrastructure | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	3,326	2,886
Infrastructure | Hybrid Infrastructure | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	2,108	1,646
Infrastructure | Infrastructure Support | Operating Segments
Revenue by Major Products/Service Offerings
Revenue	1,218	1,240
Financing | Operating Segments
Revenue by Major Products/Service Offerings
Total Revenue	$ 220	$ 191