Retirement Programs - Pension and Postretirement Benefit Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Amount recognized in Net pension and OPEB cost (benefit), excluding service cost	$ (164)	$ (237)	$ (192)
Pensions
Defined Benefit Plan Disclosure [Line Items]
Service cost	84	127	157
Interest cost	373	201	154
Expected return on plan assets	(523)	(518)	(521)
Net amortization and deferral	(30)	74	171
Settlement charges	16	6	4
Amount recognized in Net pension and OPEB cost (benefit), excluding service cost	(164)	(237)	(192)
Net periodic benefit cost (benefit)	$ (80)	$ (110)	$ (35)