Stockholders Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method	$ 712	$ 11	$ 5
Treasury Stock, Shares, Acquired	0
Common stock, par value per share	$ 1	$ 1
Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 800
Treasury Stock, Value, Acquired, Cost Method	$ 700
Treasury Stock, Shares, Acquired	36	0