Taxes on Income - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Provisional charge for one-time transition tax related to Tax Cuts and Jobs Act of 2017	$ 5,347	$ 0	$ 0
Provisional liability for one-time transition tax related to Tax Cuts and Job Act of 2017	5,100
Deferred Tax Liabilities, Undistributed Foreign Earnings	33	$ 2,044
Provisional current liability for one-time transition tax related to Tax Cuts and Jobs Act of 2017	545
Provisional noncurrent liability for one-time transition tax related to Tax Cuts and Jobs Act of 2017	$ 4,500
U.S. statutory rate applied to income before taxes (as percent)	35.00%	35.00%	35.00%
Remeasurement of deferred taxes related to Tax Cuts and Jobs Act of 2017 provisional benefit	$ 779
Deferred tax assets on NOL carryforwards relating to foreign jurisdictions	630
Deferred tax assets relating to various U.S. tax credit carryforwards and NOL carryforwards	24
Income taxes paid	4,900	$ 1,800	$ 1,800
Tax benefits relating to stock option exercises	73	147	109
Unrecognized tax benefits	1,723	3,494	3,448	$ 3,534
Favorable net impact to income tax provision if unrecognized tax benefits were recognized	1,600
Reasonably possible amount that liability for unrecognized tax benefits could decline up to in next 12 months (up to)	165
Interest and penalties associated with uncertain tax positions, expense (benefit)	183	134	102
Liabilities for accrued interest and penalties	341	886
Unrecognized tax benefits from adjustments related to examination	1,388	92	184
Proceeds from refunds			715
Income tax expense (benefit)	(4,103)	$ (718)	(942)
Foreign Jurisdiction
Income Tax [Line Items]
Valuation allowance on foreign NOL carryforwards	900
Internal Revenue Service (IRS)
Income Tax [Line Items]
Income tax expense (benefit)			$ 410
Internal Revenue Service (IRS)
Income Tax [Line Items]
Income taxes paid	2,800
Unrecognized tax benefits from adjustments related to examination	234
2017 Tax Cuts and Jobs Act (TCJA) [Member]
Income Tax [Line Items]
Deferred Tax Liabilities, Undistributed Foreign Earnings	$ 2,000