Recent Accounting Pronouncements Adoption of ASU 2014-09 Textuals (Details) - Estimate of Revenue Recognized on Open Contracts Prior to Adoption of Revenue ASU [Member] $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Revenue [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 49
Operating Income (Loss) [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	5
Retained Earnings [Member]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 4