Fair Value Measurements And Disclosure (Long-Term Debt And Other Financial Instruments) (Details) - USD ($) $ in Millions |
Jun. 30, 2020 |
Dec. 31, 2019 |
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|---|---|---|---|---|---|---|
| Carrying Amount [Member] | ||||||
| Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items] | ||||||
| Notes and debentures | [1] | $ 164,099 | $ 161,109 | |||
| Commercial paper | 3,001 | 0 | ||||
| Bank borrowings | 0 | 4 | ||||
| Investment securities | [2] | 3,632 | 3,723 | |||
| Fair Value [Member] | ||||||
| Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items] | ||||||
| Commercial paper | 3,001 | 0 | ||||
| Bank borrowings | 0 | 4 | ||||
| Investment securities | [2] | 3,632 | 3,723 | |||
| Fair Value [Member] | Level 2 [Member] | ||||||
| Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items] | ||||||
| Notes and debentures | [1] | $ 190,284 | $ 182,124 | |||
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