Supplemental Cash Flow Information (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Payments of interest and commitment fees	$ 46.7	$ 45.8
Interest Paid, Capitalized	6.0	6.0
Incurred liabilities for fixed and intangible asset additions	$ 31.6	$ 57.5