Income Taxes (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) jurisdiction tax_issue	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Income Taxes [Line Items]
Income before income taxes, income from domestic operations amount	$ 12,020	$ 8,271	$ 8,894
Income before income taxes, income from foreign operations amount	12,130	11,380	8,365
Total excess tax benefits recognized	1,000
Cumulative amount of foreign subsidiaries earnings upon which U.S. income taxes have not been provided	60,700
Deferred tax asset on prepaid cost sharing	4,409	3,468
Deferred tax liabilities on foreign earnings	4,409	3,468
Net tax credit carryforwards	1,515
Total unrecognized tax benefits	5,393	4,167	3,294	$ 2,502
Total unrecognized tax benefits that, if recognized, would affect our effective tax rate	4,258	3,614	$ 2,909
Uncertain tax positions, accrued interest and penalties	$ 493	$ 348
Number of tax jurisdictions | jurisdiction	2
Minimum
Income Taxes [Line Items]
Possible decrease in unrecognized tax benefits in next twelve months	$ 200
Maximum
Income Taxes [Line Items]
Possible decrease in unrecognized tax benefits in next twelve months	700
IRS
Income Taxes [Line Items]
Net operating loss carryforwards	$ 592
Number of tax issues planned to be litigated in court | tax_issue	1
State
Income Taxes [Line Items]
Net operating loss carryforwards	$ 681
Foreign Tax Authority
Income Taxes [Line Items]
Net operating loss carryforwards	304
Net tax credit carryforwards	$ 166