Other Income and Expense - Other Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule of other expense [Line Items]
Gain (Loss) on Disposition of Assets			$ (26)	$ (23)
Other Expenses	$ 13	$ 18	42	47
Other Expense [Member]
Schedule of other expense [Line Items]
Gain (Loss) on Disposition of Assets	(12)	(10)	(26)	(30)
Water Rights Write-Off	0	4	7	4
Legal settlement	1	0	5	8
Other Cost and Expense, Operating	$ 0	$ 4	$ 4	$ 5