Pension, Other Postretirement Benefits and Savings Plans - Amounts Recognized in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Pension Plan | United States
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	$ (3)	$ (3)
Net actuarial loss	2,353	2,380
Gross amount recognized	2,350	2,377
Deferred income taxes	(43)	(50)
Net amount recognized	2,307	2,327
Pension Plan | Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	25	25
Net actuarial loss	636	782
Gross amount recognized	661	807
Deferred income taxes	(104)	(135)
Minority shareholders’ equity	(2)	(1)
Net amount recognized	555	671
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	(7)	(23)
Net actuarial loss	30	30
Gross amount recognized	23	7
Deferred income taxes	(29)	(22)
Net amount recognized	$ (6)	$ (15)