Fair Value Measurements And Disclosure (Notional Amount Of Our Outstanding Derivative Positions) (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Derivative [Line Items] | ||
| Notional amount of outstanding derivative positions | $ 46,947 | $ 47,769 |
| Interest Rate Swaps [Member] | ||
| Derivative [Line Items] | ||
| Notional amount of outstanding derivative positions | 853 | 3,483 |
| Cross-Currency Swaps [Member] | ||
| Derivative [Line Items] | ||
| Notional amount of outstanding derivative positions | 42,325 | 42,192 |
| Interest Rate Locks [Member] | ||
| Derivative [Line Items] | ||
| Notional amount of outstanding derivative positions | 3,500 | 0 |
| Foreign Exchange Contracts [Member] | ||
| Derivative [Line Items] | ||
| Notional amount of outstanding derivative positions | $ 269 | $ 2,094 |