Earnings Per Share (EPS) - Computation of Basic and Diluted EPS Attributable to Common Stock (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Basic EPS
Net income	$ 91	$ 63
Weighted average shares of common stock outstanding (in shares)	68	70
Basic earnings per share (in dollars per share)	$ 1.32	$ 0.91
Diluted EPS
Net income	$ 91	$ 63
Weighted average shares of common stock outstanding (in shares)	68	70
Dilutive effect of stock options and restricted stock units (in shares)	1	1
Weighted average shares of common stock outstanding - diluted (in shares)	69	71
Diluted earnings per share (in dollars per share)	$ 1.31	$ 0.89
Common stock equivalents excluded from income per diluted share because of their anti-dilutive effect ( in shares )	1	1