Income Taxes (Schedule Of Reconciliation Of U.S. Federal Statutory Tax Rate To Our Effective Income Tax Rate) (Details) - USD ($) $ in Millions		3 Months Ended			12 Months Ended
		Sep. 30, 2016	Dec. 31, 2015	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Examination [Line Items]
U.S. federal statutory tax					35.00%	35.00%	35.00%
Research and development credits					(5.20%)	(3.40%)	(2.90%)
Tax basis adjustment (1)	[1]				(7.90%)		(3.60%)
U.S. manufacturing activity tax benefit					(3.80%)	(2.90%)	(1.20%)
Tax on international activities					(0.50%)	(0.60%)	(0.20%)
Excess tax benefits (2)	[2]				(1.90%)
Federal audit settlements (3)	[3]				(3.20%)		(3.60%)
Other provision adjustments					(0.40%)	(0.40%)	0.20%
Effective income tax rate					12.10%	27.70%	23.70%
Tax benefits related to reinstatement of research tax credit			$ 235
Incremental tax benefit related to tax basis adjustment		$ 440		$ 265
Excess tax benefits related to employee share-based payments					$ 105
Tax Year 2011-2012 [Member]
Income Tax Examination [Line Items]
Tax benefit related to settlement of federal tax audit		$ 177
Tax Year 2007-2008 [Member]
Income Tax Examination [Line Items]
Tax benefit related to settlement of federal tax audit				116
Tax Year 2009-2010 [Member]
Income Tax Examination [Line Items]
Tax benefit related to settlement of federal tax audit				$ 143

[1] In the third quarter of 2016 and the second quarter of 2014, we recorded incremental tax benefits of $440 and $265 related to the application of a 2012 Federal Court of Claims decision which held that the tax basis in certain assets could be increased (tax basis adjustment).

[2] Throughout 2016, we recorded tax benefits of $105 as a result of the adoption of ASU 2016-09 “Improvements to Employee Share-Based Payment Accounting” which required excess tax benefits related to employee share-based payments to be recorded through tax expense.

[3] In the third quarter of 2016, a tax benefit of $177 was recorded as a result of the settlement of the 2011-2012 federal tax audit. In the second quarter of 2014, tax benefits of $116 and $143 were recorded as a result of the 2007-2008 and 2009-2010 federal tax audit settlements.