Retirement-Related Benefits - Contributions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Retirement-Related Benefits
Total plan contributions	$ 70	$ 103
Trust for Benefit of Employees
Retirement-Related Benefits
Contributions by employer - Noncash	215	210
U.S. nonpension postretirement benefit plan
Retirement-Related Benefits
Total plan contributions	70	89
Non-U.S. DB plans and multi-employer plans
Retirement-Related Benefits
Total plan contributions	$ 1	$ 14