Common Equity - Common Stock Dividends (Details) - $ / shares					3 Months Ended		9 Months Ended
	Sep. 01, 2015	Jul. 06, 2015	Jun. 12, 2015	Apr. 16, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Dividends Paid and Payable [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.4575	$ 0			$ 0.00	$ 0.39	$ 1.29	$ 1.17
Dividend Increase Percentage		8.30%
Dividends declared April 16, 2015, payable June 1, 2015 [Member]
Dividends Paid and Payable [Line Items]
Common Stock, Dividends, Per Share, Declared				$ 0.4225
Dividends declared June 12, 2015, payable July 6, 2015 [Member]
Dividends Paid and Payable [Line Items]
Common Stock, Dividends, Per Share, Declared			$ 0.2067
Dividends declared June 12, 2015, payable September 1, 2015 [Member]
Dividends Paid and Payable [Line Items]
Common Stock, Dividends, Per Share, Declared			$ 0.2337