Retirement Benefits Activity (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2014 Qualified Pension Benefits [Member]	Sep. 30, 2014 Qualified Pension Benefits [Member]	Sep. 30, 2014 SERP Pension Benefits [Member]	Sep. 30, 2014 SERP Pension Benefits [Member]	Sep. 30, 2014 Other Benefit [Member]	Sep. 30, 2014 Other Benefit [Member]	Sep. 30, 2014 Subsidiaries [Member]	Dec. 31, 2014 Scenario, Forecast [Member] Qualified Pension Benefits [Member]	Dec. 31, 2014 Scenario, Forecast [Member] SERP Pension Benefits [Member]	Dec. 31, 2014 Scenario, Forecast [Member] Other Benefit [Member]	Dec. 31, 2014 Scenario, Forecast [Member] Subsidiaries [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent							1.00%				4.00%
Aggregate expected contributions								$ 12.0	$ 4.0	$ 0.3
Company Contribution	$ 3.0	$ 9.0	$ 0.5	$ 1.4	$ 0.1	$ 0.4