Financial Instruments and Risk Management (Schedule of Available-for-sale Securities Reconciliation) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 55.6	$ 27.7
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0.0	0.5
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(1.6)	0.0
Fair Value	54.0	28.2
Debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28.3	27.7
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0.0	0.4
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(0.3)	0.0
Fair Value	28.0	28.1
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27.3	0.0
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0.0	0.1
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(1.3)	0.0
Fair Value	$ 26.0	$ 0.1