Pension, Other Postretirement Benefits and Savings Plans - Amounts Recognized in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	$ (23)	$ (32)
Net actuarial loss	30	25
Gross amount recognized	7	(7)
Deferred income taxes	(22)	(19)
Minority shareholders’ equity	0	0
Net amount recognized	(15)	(26)
United States | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	(3)	(3)
Net actuarial loss	2,380	2,493
Gross amount recognized	2,377	2,490
Deferred income taxes	(50)	(77)
Minority shareholders’ equity	0	0
Net amount recognized	2,327	2,413
Non-U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service (credit) cost	25	31
Net actuarial loss	782	611
Gross amount recognized	807	642
Deferred income taxes	(135)	(105)
Minority shareholders’ equity	(1)	(1)
Net amount recognized	$ 671	$ 536