Income Taxes, Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended			24 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2015
Income Tax Narrative (Textual)
Applicable statutory income tax rate (percent)		19.60%	29.80%	27.10%
Income tax benefit resulting from effect of tax reform adjustments, including components for which we recorded a provisional amount and components that were incomplete			$ 1,862
Income tax benefit from the remeasurement of U.S. deferred income tax assets and liabilities			2,643		$ 2,643
Tax on the deemed repatriation of the accumulated earnings and profits of our international subsidiaries			734
Cumulative undistributed earnings and profits of international subsidiaries			4,700
Recognition of foreign withholding tax, net of U.S. federal tax benefit			47		47
Overall income tax benefit with respect to Tax Reform		$ 12
Increase in valuation allowance		613
Increase in one-time transition tax for completion of accounting	$ 6	6
Foreign tax credit related to one-time transition tax	32	32
Cash and cash equivalents	2,982	2,982	5,850	$ 4,816	2,982	$ 4,114
Undistributed earnings of international subsidiaries	5,300	5,300			5,300
Tax refund claim not presented in our balance sheets	277	277	274		277
Income tax benefits if recognized that would impact the effective tax rate	807	807	793		807
Interest expense and penalties accrued	88	$ 88	$ 77		88
U.S. [Member]
Income Tax Narrative (Textual)
Applicable statutory income tax rate (percent)		21.00%	35.00%	35.00%
International Subsidiaries [Member]
Income Tax Narrative (Textual)
Cash and cash equivalents	2,400	$ 2,400			2,400
U.S. foreign [Member]
Income Tax Narrative (Textual)
Applicable statutory income tax rate (percent)		15.30%	17.10%	17.70%
Excess tax credits related to limitation income	$ 575	$ 575			$ 575