Fair Value Measurements - Schedule of Fair Values of Financial Liabilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Level 1
Liabilities:
Long-term debt, including current portion	$ 0	$ 0
Level 2
Liabilities:
Long-term debt, including current portion	1,844.0	1,931.9
Level 3
Liabilities:
Long-term debt, including current portion	0	0
Total
Liabilities:
Long-term debt, including current portion	1,844.0	1,931.9
Carrying Value
Liabilities:
Long-term debt, including current portion	$ 1,863.9	$ 1,927.7