Common Equity (Common Share Activity) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Common Stock Oustanding [Roll Forward]
Shares outstanding, January 1 (in shares)	110,943,669	110,987,400	111,018,821
Equity-based compensation plans (in shares)	35,547	(23,374)	20,195
Other (in shares)	(43,536)	(20,357)	(51,616)
Shares outstanding, December 31 (in shares)	110,935,680	110,943,669	110,987,400