Income Taxes (Valuation Allowance - Text) (Details) - U.S. net deferred income tax assets [Member] - Deferred tax assets related to purchases of limited partnerships and joint venture interests [Member] $ in Millions	12 Months Ended
Dec. 31, 2013 USD ($)
Income Tax Contingency [Line Items]
Change in valuation allowance	$ 67.7
Income tax expense (benefit) [Member]
Income Tax Contingency [Line Items]
Change in valuation allowance	52.0
Discrete income tax benefit attributable to valuation allowance release	44.8
Additional paid-in capital [Member]
Income Tax Contingency [Line Items]
Change in valuation allowance	$ 15.7

Income Taxes (Valuation Allowance - Text) (Details) - U.S. net deferred income tax assets [Member] - Deferred tax assets related to purchases of limited partnerships and joint venture interests [Member]
$ in Millions

12 Months Ended

Dec. 31, 2013

USD ($)

Income Tax Contingency [Line Items]

Change in valuation allowance

$ 67.7

Income tax expense (benefit) [Member]

Income Tax Contingency [Line Items]

Change in valuation allowance

52.0

Discrete income tax benefit attributable to valuation allowance release

44.8

Additional paid-in capital [Member]

Income Tax Contingency [Line Items]

Change in valuation allowance

$ 15.7