Lease Obligations (Minimum future lease commitments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Operating Lease Obligations [Abstract]
Operating leases, future minimum payments due, next twelve months	$ 37.2
Operating leases, future minimum payments, due in two years	23.4
Operating leases, future minimum payments, due in three years	14.6
Operating leases, future minimum payments, due in four years	7.0
Operating leases, future minimum payments, due in five years	4.0
Operating leases, future minimum payments, due thereafter	0.8
Operating leases, future minimum payments due	87.0
Capital Lease Obligations [Abstract]
Capital leases, future minimum payments due, next twelve months	31.2
Capital leases, future minimum payments due in two years	21.5
Capital leases, future minimum payments due in three years	16.5
Capital leases, future minimum payments due in four years	9.0
Capital leases, future minimum payments due in five years	3.6
Capital leases, future minimum payments due thereafter	0.4
Capital leases, future minimum payments due	82.2
Capital leases, future minimum payments, interest included in payments	(3.2)
Capital lease obligations	79.0
Capital lease obligations, current	(31.0)
Capital lease obligations, noncurrent	$ 48.0