Financial Instruments and Risk Management (Impact of Cash Flow Hedges on Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification of net losses to earnings, net of taxes		$ 1.3	$ 1.9	$ 1.9
Treasury Locks [Member]
Balance at Period Start	[1]	(4.0)	(5.9)
Reclassification of net losses to earnings, net of taxes		4.0	1.9
Balance at Period End	[1]	0.0	(4.0)	(5.9)
Net unamortized losses at beginning of year, tax effect		2.7	2.7
Reclassification of net losses to earnings, tax effect		0.0	0.0
Net unamortized losses at end of year, tax effect		$ 0.0	$ 2.7	$ 2.7

[1] Amounts above exclude taxes of $2.7 at the beginning of year in 2016 and 2015 and at the end of year in 2015.