Common Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	9 Months Ended
	Oct. 03, 2016	Oct. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Common Shareholders' Equity [Line Items]
Common Stock, Shares Authorized			600,000,000		250,000,000
Common Stock Shares Authorized Prior to Amended Articles of Incorporation			250,000,000
Net Proceeds from Issuance of Common Stock			$ 2.4	$ 2.3
Common Stock [Member]
Common Shareholders' Equity [Line Items]
Stock Issued During Period, Shares, New Issues			420,207	210,579
Common Stock [Member] | Subsequent Event [Member]
Common Shareholders' Equity [Line Items]
Shares Issued, Price Per Share	$ 26.45	$ 26.45
Net Proceeds from Issuance of Common Stock	$ 1,550.0	$ 1,550.0
Gross Proceeds from Issuance of Common Stock	$ 1,600.0	$ 1,600.0
Stock Issued During Period, Shares, New Issues	60,500,000	60,500,000