Equity And Earnings Per Share (Diluted Table) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Diluted earnings per share:
Net income available for common stockholders	$ 46	$ 36	$ 124	$ 117
Weighted Average Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic	78,509,625	76,742,789	77,543,008	75,910,080
Potentially dilutive common shares:
Issuable pursuant to employee incentive plans	610,923	606,187	700,691	736,407
Weighted Average Number of Shares Outstanding, Diluted	79,120,548	77,348,976	78,243,699	76,646,487
Earnings Per Share, Diluted	$ 0.58	$ 0.45	$ 1.58	$ 1.52
Common Class A [Member]
Weighted Average Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic	78,509,525	76,742,689	77,542,908	75,909,980
Common Class B [Member]
Weighted Average Shares Outstanding [Abstract]
Weighted Average Number of Shares Outstanding, Basic	100	100	100	100

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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