v3.19.3.a.u2
Pension And Other Postretirement Benefits (Benefit Obligations And Plan Assets Associated With Principal Benefit Plans) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]      
Medicare subsidy receipts $ 20 $ 13  
U.S. [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 3.50% 4.40%  
Long-term rate of compensation increase 5.75% 5.75%  
Benefit obligation at January 1 $ 18,174 $ 19,310  
Service cost 757 819 $ 784
Interest cost 766 721 798
Defined benefit plan, actuarial net (gains) losses 2,562 (957)  
Benefits paid [1],[2] (1,300) (1,715)  
Amendments, divestments and other   (4)  
Benefit obligation at December 31 20,959 18,174 19,310
Accumulated benefit obligation at December 31 $ 16,387 $ 14,683  
Pension Benefits - Non-U.S. [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 2.30% 3.00%  
Long-term rate of compensation increase 4.80% 4.30%  
Benefit obligation at January 1 $ 25,378 $ 27,963  
Service cost 551 608 596
Interest cost 763 754 772
Defined benefit plan, actuarial net (gains) losses 3,703 (1,034)  
Benefits paid [1],[2] (1,196) (1,284)  
Foreign exchange rate changes 391 (1,664)  
Amendments, divestments and other 328 35  
Benefit obligation at December 31 29,918 25,378 27,963
Accumulated benefit obligation at December 31 $ 27,236 $ 23,350  
Other Postretirement Benefits [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Discount rate 3.50% 4.40%  
Long-term rate of compensation increase 5.75% 5.75%  
Benefit obligation at January 1 $ 7,471 $ 8,100  
Service cost 139 152 129
Interest cost 315 301 317
Defined benefit plan, actuarial net (gains) losses 556 (630)  
Benefits paid [1],[2] (517) (528)  
Foreign exchange rate changes 25 (49)  
Amendments, divestments and other 124 125  
Benefit obligation at December 31 $ 8,113 $ 7,471 $ 8,100
[1] Benefit payments for funded and unfunded plans.
[2] For 2019 and 2018, other postretirement benefits paid are net of $20 million and $13 million of Medicare subsidy receipts, respectively.