Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Narrative (Details)

v3.20.4
Employee Benefit Plans - Narrative (Details) - USD ($)
shares in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]      
Increase (decrease) from change in weighted average discount rates $ 1,900,000,000 $ 2,200,000,000  
Cost recognized $ 1,200,000,000 $ 1,000,000,000.0 $ 1,000,000,000.0
Number of common stock shares held in plan (in shares) 189 189  
Dividend payments to the plan $ 138,000,000 $ 133,000,000 $ 115,000,000
U.S. | Pension Plan | Qualified      
Defined Benefit Plan Disclosure [Line Items]      
Company contributions $ 0 0  
Percentage of prior years market gains (losses) recognized at next measurement date 60.00%    
Percentage of prior years market gains (losses) recognized equally over four year period 40.00%    
U.S. | Pension Plan | Qualified | Equity securities      
Defined Benefit Plan Disclosure [Line Items]      
Amount of employer and related party securities included in plan assets $ 274,000,000 $ 315,000,000  
Actual plan asset allocations 1.26% 1.55%  
U.S. | Other Pension Plan      
Defined Benefit Plan Disclosure [Line Items]      
Company contributions $ 0 $ 0  
U.S. | Other Pension Plan | Nonqualified      
Defined Benefit Plan Disclosure [Line Items]      
Company contributions 86,000,000 91,000,000  
Estimated future employer contributions in next fiscal year 93,000,000    
U.S. | Postretirement Health and Life Plans      
Defined Benefit Plan Disclosure [Line Items]      
Company contributions 6,000,000 24,000,000  
Estimated future employer contributions in next fiscal year $ 14,000,000    
Percentage of unrecognized gain (loss) recognized during the period 50.00%    
Health care cost trend rate assumed for next fiscal year 6.25%    
Ultimate health care cost trend rate 5.00%    
Non-U.S. | Pension Plan      
Defined Benefit Plan Disclosure [Line Items]      
Company contributions $ 23,000,000 $ 20,000,000  
Estimated future employer contributions in next fiscal year $ 29,000,000