Supplemental Cash Flow Information (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Supplemental Cash Flow Elements [Abstract]
Payments of interest and commitment fees	$ 78.4	$ 40.3
Interest Paid, Capitalized	12.3	7.2
Incurred liabilities for fixed and intangible asset additions	55.6	$ 52.9
Other Asset Additions Incurred but Not yet Paid	$ 0.1