Property, Plant And Equipment (Narrative) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Property, Plant and Equipment [Line Items] | ||||
| Depreciation expense | $ 20,285 | $ 20,083 | $ 19,761 | |
| Assets Disposed of by Method Other than Sale, in Period of Disposition, Gain (Loss) on Disposition | (1,458) | (46) | (2,914) | |
| Copper Network Assets [Member] | ||||
| Property, Plant and Equipment [Line Items] | ||||
| Assets Disposed of by Method Other than Sale, in Period of Disposition, Gain (Loss) on Disposition | $ 1,290 | 2,883 | ||
| Software [Member] | ||||
| Property, Plant and Equipment [Line Items] | ||||
| Depreciation expense | $ 3,313 | $ 3,092 | $ 2,810 | |