Retirement-Related Benefits - U.S. Retirement Plan Changes (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Retirement-Related Benefits
Pension settlement charge		$ 2,700	$ 0	$ 2,725
Pension settlement charge, net of tax		2,000
Personal Pension Plan (PPP)
Retirement-Related Benefits
Benefit plan assets transferred from plan	$ 6,000
Benefit plan obligations transferred from plan	$ 6,000
Pension settlement charge		2,700
Pension settlement charge, net of tax		$ 2,000