Income Taxes (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Operating Loss Carryforwards [Line Items] | |||
| Net operating and capital loss carryforwards (tax effected) for federal income tax purposes | $ 585 | ||
| Net operating and capital loss carryforwards (tax effected) for state income tax purposes | 916 | ||
| Net operating and capital loss carryforwards (tax effected) for foreign income tax purposes | 2,763 | ||
| Amount of deposits that reduced UTB balance | 702 | $ 2,584 | |
| Accrued interest and penalties included in unrecognized tax benefits balance at year end | 2,450 | 2,708 | |
| Net interest and penalty expense included in income tax expense | 149 | $ 267 | $ 1,290 |
| Federal | |||
| Operating Loss Carryforwards [Line Items] | |||
| Tax credit carryforwards | 1,080 | ||
| State | |||
| Operating Loss Carryforwards [Line Items] | |||
| Tax credit carryforwards | $ 2,011 | ||