Stock Inventive and Ownership Plans Employee Stock Purchase Plan (Tables)

12 Months Ended

Dec. 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Compensation, Employee Stock Purchase Plan, Activity [Table Text Block]

Information related to shares issued or to be issued in connection with the employee stock purchase plan based on employee contributions and the range of purchase prices is as follows:

	Year Ended December 31,
	2018		2017		2016
Shares issued or to be issued (in thousands)	2,452		2,491		2,337
Range of purchase prices	$21.49 - $27.91		$18.60 - $21.07		$15.29 - $18.39
Expense recognized (in millions)	$	17	$	13	$	11