Stockholders' Equity (Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stockholders' Equity [Abstract]
Net income	$ 9	$ 18
Less: Dividends on Series A Preferred Stock	6	6
Net income attributable to common stockholders	$ 3	$ 12
Weighted average basic shares outstanding	81.7	84.3
Effect of dilutive securities	0.7	1.0
Weighted average diluted shares outstanding	82.4	85.3
Net income per share:
Basic	$ 0.04	$ 0.14
Diluted	$ 0.04	$ 0.14