Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015
Accumulated other comprehensive income in the equity section of the balance sheet included
Defined Benefit Plans, Beginning Balance		$ (443)
Foreign Currency Translation, Beginning Balance	[1]	(5,804)
Accumulated Other Comprehensive Income, Beginning Balance		(6,247)
Defined Benefit Plans		(82)		$ 32
Foreign Currency Translation		1,183	[1]	(2,719)
Other Comprehensive Income, Net of Tax		1,101		$ (2,687)
Defined Benefit Plans, Ending Balance		(525)
Foreign Currency Translation, Ending Balance	[1]	(4,621)
Accumulated Other Comprehensive Income, Ending Balance		$ (5,146)

[1] Foreign Currency Translation increased due to the weakening of the U.S. dollar relative to the Canadian dollar and Norwegian krone.