Retirement-Related Benefits - Contributions (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Retirement-Related Benefits
Total plan contributions	$ 150	$ 163
Trust for Benefit of Employees
Retirement-Related Benefits
Contributions by employer - Noncash	390	347
U.S. nonpension postretirement benefit plan
Retirement-Related Benefits
Total plan contributions	110	134
Non-U.S. DB plans and multi-employer plans
Retirement-Related Benefits
Total plan contributions	$ 40	$ 29