Other Income (Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Income (Expense) [Abstract]
AFUDC - Equity	$ 2.1	$ 1.2	$ 5.9	$ 3.4
Gain on Sale of Available-for-sale Securities	0	1.4	0.2	2.2
Investments and Other Expense			(0.1)
Investments and Other Income	0	0.7		1.9
Total Other Income	$ 2.1	$ 3.3	$ 6.0	$ 7.5