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Equity And Earnings Per Share (Basic Table) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Basic earnings per share:
Net income available for common stockholders	$ 76	$ 84	$ 49
Weighted average shares of common stock outstanding:
Weighted Average Number of Shares Outstanding, Basic	69,926,933	66,013,247	61,043,071
Basic earnings per share	$ 1.09	$ 1.28	$ 0.80
Common Class A
Weighted average shares of common stock outstanding:
Weighted Average Number of Shares Outstanding, Basic	69,926,833	66,013,147	61,042,971
Common Class B
Weighted average shares of common stock outstanding:
Weighted Average Number of Shares Outstanding, Basic	100	100	100

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