Asset Impairment and Exit Costs (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Cash payments related to exit costs	$ 8	$ 44	$ 22	$ 204
Restructuring Reserve	$ 32		$ 32		$ 54