Future Minimum Lease Payments (Details) $ in Millions	Dec. 31, 2017 USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Rent Obligations, due 2018	$ 335.0
Rent Obligations, due 2019	312.1
Rent Obligations, due 2020	285.3
Rent Obligations, due 2021	251.4
Rent Obligations, due 2022	204.1
Rent Obligations, due thereafter	727.2
Total Rent Obligations	2,115.1
Sublease Rental Income, due 2018	(4.2)
Sublease Rental Income, due 2019	(3.8)
Sublease Rental Income, due 2020	(2.5)
Sublease Rental Income, due 2021	(1.4)
Sublease Rental Income, due 2022	(0.8)
Sublease Rental Income, due thereafter	(0.5)
Total Sublease Rental Income	(13.2)
Net Rent, due 2018	330.8
Net Rent, due 2019	308.3
Net Rent, due 2020	282.8
Net Rent, due 2021	250.0
Net Rent, due 2022	203.3
Net Rent, due thereafter	726.7
Total Net Rent	$ 2,101.9

Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, Current

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Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, Due in Three Years

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Contractually required future rental payments receivable on noncancelable subleasing arrangements.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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