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Equity And Earnings Per Share (Basic Table) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Basic earnings per share:
Net income available for common stockholders	$ 23	$ 27	$ 47	$ 60
Weighted average shares of common stock outstanding:
Weighted Average Number of Shares Outstanding, Basic	69,087,853	64,967,364	68,539,526	64,476,421
Basic earnings per share	$ 0.33	$ 0.41	$ 0.68	$ 0.93
Common Class A
Weighted average shares of common stock outstanding:
Weighted Average Number of Shares Outstanding, Basic	69,087,753	64,967,264	68,539,426	64,476,321
Common Class B
Weighted average shares of common stock outstanding:
Weighted Average Number of Shares Outstanding, Basic	100	100	100	100

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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