Fair Value Measurements - Table 1 (Details) (Restricted Marketable Securities [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Prepaid Expenses and Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	$ 4.7	$ 16.4
Fair Value, Valuation Techniques	M	M
Prepaid Expenses and Other Current Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	0	0
Prepaid Expenses and Other Current Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	4.7	16.4
Prepaid Expenses and Other Current Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	0	0
Other Long-Term Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	42.9	39.4
Fair Value, Valuation Techniques	M	M
Other Long-Term Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	0	0
Other Long-Term Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	42.9	39.4
Other Long-Term Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]
Available-for-sale Securities, Fair Value	$ 0	$ 0