Lease Obligations (Operating Leases) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Lease Terms in Excess of One Year [Member]
Operating Leased Assets [Line Items]
Operating leases, rent expense (in dollars)	$ 71.5	$ 53.3	$ 47.3
Lease Terms in Excess of One Year [Member] | Minimum [Member]
Operating Leased Assets [Line Items]
Operating leases, term of contract (in years)	1 year	1 year	1 year
Lease Terms of One Year or Less [Member]
Operating Leased Assets [Line Items]
Operating leases, rent expense (in dollars)	$ 191.7	$ 200.1	$ 175.2
Lease Terms of One Year or Less [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Operating leases, term of contract (in years)	1 year	1 year	1 year