Derivative Financial Instruments and Related Hedging Programs, Offsetting of Derivative Instruments by Counterparty (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets	$ 81.8	$ 58.5
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	81.8	58.5
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	1.2	1.2
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0	0
Net Amount	80.6	57.3
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Liabilities	(86.1)	(66.7)
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	(86.1)	(66.7)
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	(1.2)	(1.2)
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0	0
Net Amount	(84.9)	(65.5)
Counterparty (with Netting Agreements)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets	1.0	2.3
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	1.0	2.3
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0.8	1.0
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0	0
Net Amount	0.2	1.3
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Liabilities	(1.6)	(1.7)
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	(1.6)	(1.7)
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	(0.8)	(1.0)
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0	0
Net Amount	(0.8)	(0.7)
Counterparty (without Netting Agreements)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets	80.4	55.9
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	80.4	55.9
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0	0
Net Amount	80.4	55.9
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Liabilities	(83.2)	(63.8)
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	(83.2)	(63.8)
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0	0
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0	0
Net Amount	(83.2)	(63.8)
Counterparty (with partial Netting Agreements)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Assets	0.4	0.3
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Assets Presented in the Consolidated Balance Sheets	0.4	0.3
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	0.4	0.2
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Received	0	0
Net Amount	0	0.1
Derivative Liability, Fair Value, Amount Not Offset Against Collateral [Abstract]
Gross Amounts of Recognized Liabilities	(1.3)	(1.2)
Gross Amounts Offset in the Consolidated Balance Sheets	0	0
Net Amounts of Liabilities Presented in the Consolidated Balance Sheets	(1.3)	(1.2)
Gross Amounts Not Offset in the Consolidated Balance Sheets - Financial Instruments	(0.4)	(0.2)
Gross Amounts Not Offset in the Consolidated Balance Sheets - Cash Collateral Pledged	0	0
Net Amount	$ (0.9)	$ (1.0)