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Equity And Earnings Per Share (Diluted Table) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Diluted earnings per share:
Net income available for common stockholders	$ 46	$ 49
Weighted Average Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic	76,751,168	75,101,062
Potentially dilutive common shares:
Issuable pursuant to employee incentive plans	817,296	876,449
Weighted Average Number of Shares Outstanding, Diluted	77,568,464	75,977,511
Earnings Per Share, Diluted	$ 0.60	$ 0.64
Common Class A
Weighted Average Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic	76,751,068	75,100,962
Common Class B
Weighted Average Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic	100	100

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