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Taxes on Income - Narrative (Details) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Income Tax [Line Items] |  |  |  |
U.S. statutory rate applied to income before taxes (as percent) | 21.00% | 35.00% | 35.00% |
Impact of the TCJA (as percent) | 3.30% | 40.30% | 0.00% |
Charge for one-time transition tax related to Tax Cuts and Jobs Act of 2017 | $ 0 | $ 5,347,000,000 | $ 0 |
Reversal of deferred tax previously recorded |  | 2,000,000,000 |  |
Measurement-period adjustment | 124,000,000 |  |  |
Transition tax liability | 4,900,000,000 | 5,500,000,000 |  |
Remeasurement of deferred taxes related to Tax Cuts and Jobs Act of 2017 provisional benefit |  | 779,000,000 |  |
Measurement period adjustments related to deferred income taxes | 32,000,000 |  |  |
Deferred tax assets on NOL carryforwards relating to foreign jurisdictions | 715,000,000 |  |  |
NOL carryforwards relating to U.S. jurisdictions | 0 |  |  |
Income taxes paid | 1,500,000,000 | 4,900,000,000 | 1,800,000,000 |
Tax benefits relating to stock option exercises | 77,000,000 | 73,000,000 | 147,000,000 |
Unrecognized tax benefits | 1,893,000,000 | 1,723,000,000 | 3,494,000,000 | $ 3,448,000,000
Favorable net impact to income tax provision if unrecognized tax benefits were recognized | 1,800,000,000 |  |  |
Reasonably possible amount that liability for unrecognized tax benefits could decline up to in next 12 months (up to) | 750,000,000 |  |  |
Interest and penalties associated with uncertain tax positions, expense (benefit) | 51,000,000 | 183,000,000 | 134,000,000 |
Liabilities for accrued interest and penalties | 372,000,000 | 341,000,000 |  |
Unrecognized tax benefits from adjustments related to examination | 91,000,000 | 1,388,000,000 | $ 92,000,000 |
Foreign Jurisdiction |  |  |  |
Income Tax [Line Items] |  |  |  |
Valuation allowance on foreign NOL carryforwards | 1,300,000,000 |  |  |
Federal | Internal Revenue Service (IRS) |  |  |  |
Income Tax [Line Items] |  |  |  |
Income taxes paid |  | 2,800,000,000 |  |
Unrecognized tax benefits from adjustments related to examination |  | $ 234,000,000 |  |
Income Taxes Payable |  |  |  |
Income Tax [Line Items] |  |  |  |
Transition tax liability, current | 275,000,000 |  |  |
Other Noncurrent Liabilities |  |  |  |
Income Tax [Line Items] |  |  |  |
Transition tax liability, noncurrent | $ 4,600,000,000 |  |  |

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