Postretirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension and Other Postretirement Benefits
Pension and other postretirement benefit contributions
Contributions to pension and other postretirement benefit plans	$ 210
Expected full year contributions to pension and other postretirement benefit plans during the year	357
Other Postretirement Benefits Plan
Components of net periodic benefit cost:
Service cost	25	$ 25
Interest cost	20	16
Expected return on plan assets	(4)	(2)
Amortization of prior service cost / (credit)	(1)	(10)
Net periodic benefit cost (benefit)	40	29
UNITED STATES
Components of net periodic benefit cost:
Service cost	0	0
Interest cost	100	82
Expected return on plan assets	(167)	(179)
Amortization of prior service cost / (credit)	0	0
Net periodic benefit cost (benefit)	(67)	(97)
Foreign Plan
Components of net periodic benefit cost:
Service cost	13	14
Interest cost	18	14
Expected return on plan assets	(34)	(32)
Amortization of prior service cost / (credit)	0	0
Net periodic benefit cost (benefit)	$ (3)	$ (4)