Common Equity (Common Share Activity) (Details) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Stock Oustanding [Roll Forward]
Shares outstanding, January 1 (in shares)	110,935,680	110,943,669	110,987,400
Common stock issued during the period, Shareowner Direct Plan (in shares)	303,005	0	0
Equity-based compensation plans (in shares)	56,378	35,547	(23,374)
Other (in shares)	(22,464)	(43,536)	(20,357)
Shares outstanding, December 31 (in shares)	113,459,216	110,935,680	110,943,669
At The Market Offering Program [Member]
Common Stock Oustanding [Roll Forward]
Common stock issued during the period, At-the-market offering program (in shares)	2,186,617	0	0