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Common Equity (Common Share Activity) (Details) | 9 Months Ended
--- | ---
Sep. 30, 2017 shares
Common Stock Oustanding [Roll Forward] |
Shares outstanding, January 1, 2017 (in shares) | 227,673,654
Shareowner Direct Plan issuances (in shares) | 496,437
Equity-based compensation plans (in shares) | 5,185
Other (in shares) | (45,847)
Shares outstanding, September 30, 2017 (in shares) | 231,204,360
At-The-Market Offering Program [Member] |
Common Stock Oustanding [Roll Forward] |
At-the-market offering program (in shares) | 3,074,931

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