v3.19.3.a.u2
Fair Value Measurements And Disclosure (Long-Term Debt And Other Financial Instruments) (Details) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]    
Notes and debentures $ 161,109 $ 171,529
Commercial paper 0 3,048
Bank borrowings [1] 4 4
Carrying Amount [Member]    
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]    
Notes and debentures [2] 161,109 171,529
Commercial paper 0 3,048
Bank borrowings 4 4
Investment securities [3] 3,723 3,409
Fair Value [Member]    
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]    
Commercial paper 0 3,048
Bank borrowings 4 4
Investment securities [3] 3,723 3,409
Fair Value [Member] | Level 2 [Member]    
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]    
Notes and debentures [2] $ 182,124 $ 172,287
[1] Outstanding balance of short-term credit facility of a foreign subsidiary.
[2] Includes credit agreement borrowings.
[3] Excludes investments accounted for under the equity method.