Income Taxes Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets (1):
Excluding net operating losses U.S. - Federal/States	[1],[2]	$ 107	$ 357
Net operating losses foreign	[1],[3]	856	669
Accrued liabilities, reserves, & other expenses		854	780
Stock-based compensation		727	534
Deferred revenue		189	156
Assets held for investment		148	154
Depreciation and amortization		222	117
Other items		268	125
Tax credits	[1],[4]	41	115
Total gross deferred tax assets		3,412	3,007
Less valuation allowance	[5]	(1,069)	(901)
Deferred tax assets, net of valuation allowance		2,343	2,106
Deferred tax liabilities:
Depreciation & amortization		(1,970)	(1,609)
Acquisition related intangible assets		(203)	(195)
Other items		(88)	(31)
Net deferred tax assets, net of valuation allowance		82	271
Stock Based Compensation Expense
Deferred tax assets (1):
Excluding net operating losses U.S. - Federal/States		380	261
Net operating losses foreign		2	2
Tax credits		$ 447	$ 268

[1] Deferred tax assets related to net operating losses and tax credits are presented net of tax contingencies.

[2] Excluding $380 million and $261 million of deferred tax assets as of December 31, 2015 and 2014, related to net operating losses that result from excess stock-based compensation and for which any benefit realized will be recorded to stockholders’ equity.

[3] Excluding $2 million of deferred tax assets as of December 31, 2015 and 2014, related to net operating losses that result from excess stock-based compensation and for which any benefit realized will be recorded to stockholders’ equity.

[4] Excluding $447 million and $268 million of deferred tax assets as of December 31, 2015 and 2014, related to tax credits that result from excess stock-based compensation and for which any benefit realized will be recorded to stockholders’ equity.

[5] Relates primarily to deferred tax assets that would only be realizable upon the generation of net income in certain foreign taxing jurisdictions and future capital gains.