Income Taxes (Reconciliation of Deferred Tax Asset Valuation Allowance) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Income Taxes [Abstract] | |||
| Beginning balance | $ 9,965 | $ 10,214 | $ 3,040 |
| Deferred Tax Asset, Valuation Allowance, Charged To Expense | 45 | (460) | 225 |
| Deferred Tax Assets, Valuation Allowance, Other | (1,578) | (709) | 7,399 |
| Ending balance | $ 8,342 | $ 9,965 | $ 10,214 |