Segment and Geographic Reporting Geographic Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 3,340	$ 3,720	$ 3,979	$ 3,565	$ 3,982	$ 4,557	$ 4,867	$ 4,666	$ 14,604	$ 18,072	$ 17,785
Other revenues from operations									1,386	1,250	988
Property, plant and equipment, net	9,535				8,812				9,535	8,812
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									9,672	13,086	13,171
Other revenues from operations									1,304	1,169	937
Property, plant and equipment, net	7,221				6,760				7,221	6,760
Geographic information, Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									1,480	1,507	1,339
Other revenues from operations									0	0	0
Property, plant and equipment, net	464				423				464	423
Geographic information, Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									3,452	3,479	3,275
Other revenues from operations									82	81	$ 51
Property, plant and equipment, net	$ 1,850				$ 1,629				$ 1,850	$ 1,629