Financing and Capitalization (Summary of Stock Issuances) (Details) - USD ($) $ in Millions	1 Months Ended
May 31, 2018	Jun. 30, 2017
Debt Disclosure [Abstract]
Common stock issued (in shares)	638,898	1,494,371
Common stock issued	$ 29	$ 70

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

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