Income Taxes (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Mar. 31, 2019 |
|
| Income Taxes [Line Items] | ||||
| Federal corporate income tax rate | 21.00% | 35.00% | ||
| Reduction of net deferred tax liabilities | $ 31 | $ 120 | $ 12,682 | |
| Deferred tax liability attributable to temporary differences in other comprehensive income | 118 | |||
| Change in net deferred tax liability related to acquisitions | 1,000 | |||
| Net deferred tax liability, franchise rights | 15,400 | |||
| Liability for uncertain tax positions | 1,013 | 1,012 | $ 809 | |
| Unrecognized tax benefits that would impact effective tax rate | 1,100 | |||
| Unrecognized tax benefits, interest on income taxes accrued | 186 | $ 203 | ||
| Federal Tax Authority [Member] | ||||
| Income Taxes [Line Items] | ||||
| Operating loss carryforwards | 274 | |||
| Foreign Tax Authority [Member] | ||||
| Income Taxes [Line Items] | ||||
| Operating loss carryforwards | $ 5,600 | |||
| Sky Limited [Member] | ||||
| Income Taxes [Line Items] | ||||
| Deferred tax assets related to net operating losses | $ 1,200 | |||