Supplemental Cash Flow Information (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Payments of interest and commitment fees	$ 107.5	$ 115.9
Interest paid, capitalized	1.7	2.0
Incurred liabilities for fixed and intangible asset additions	$ 15.1	$ 18.6

Future cash outflow to pay for purchases of fixed assets that have occurred.

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Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.

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