Recent Accounting Pronouncements Revenue recognition (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Goods and Services Sold	$ 1,336	$ 1,121
Selling, General and Administrative Expense	147	103
Operating Income (Loss)	343	170
Non-operating pension and other postretirement employee benefit (expense) income	$ (26)	(22)
Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Goods and Services Sold		1,119
Selling, General and Administrative Expense		83
Operating Income (Loss)		192
Non-operating pension and other postretirement employee benefit (expense) income		0
Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of Goods and Services Sold		(2)
Selling, General and Administrative Expense		(20)
Operating Income (Loss)		(22)
Non-operating pension and other postretirement employee benefit (expense) income		$ (22)
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ 0
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ 0