Income Taxes Income Taxes (Net Deferred Tax Assets and Liabilities Restated for ASU 2015-17) (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net, Current
Deferred Tax Assets, Net, Noncurrent			$ 317
Deferred Tax Liabilities, Net, Current
Deferred Tax Liabilities, Net, Noncurrent		$ (2,392)	$ (2,207)
Deferred Tax Liabilities, Net	[1]	$ (2,127)	(1,890)
Scenario, Previously Reported [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Net, Current			18
Deferred Tax Assets, Net, Noncurrent			6,576
Deferred Tax Liabilities, Net, Current			$ (8,484)
Deferred Tax Liabilities, Net, Noncurrent
Deferred Tax Liabilities, Net			$ (1,890)

[1] Included in the net deferred tax (liabilities)/assets as of December 31, 2015 and 2014 are deferred tax assets in the amounts of $7,277 and $8,007 related to Accumulated other comprehensive loss.