Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

The following table sets forth the computation of basic and diluted earnings per share:

	Year ended December 31,
Share amounts in millions	2019	2018	2017
Denominator for basic earnings per share:
Weighted average common shares outstanding	123	143	144
Effect of dilutive securities:
Dilutive effect of employee stock plans	—	1	2
Dilutive potential common shares	123	144	146
Denominator for diluted earnings per share:
Adjusted weighted average shares	123	144	146