Leases

We lease substantially all our office space under operating leases and certain equipment under operating and capital leases that expire at various dates. Office leases may provide for additional renewal periods at our option. In circumstances where the exercise of the renewal option is reasonably assured at the inception of the lease, the renewal period is included in the determination of the lease term. Additionally, office leases may include scheduled rent increases and concessions, such as rent abatements and landlord incentives and tenant improvement allowances. Scheduled rent increases are recognized on a straight-line basis over the lease term. Concessions are recorded as deferred rent and are amortized to rent expense on a straight-line basis over the lease term. Certain office leases require payment of real estate taxes and other occupancy costs. These costs are not included in rent expense. Leasehold improvements made at inception or during the lease term are amortized over the shorter of the asset life or the lease term, which may include renewal periods where the renewal is reasonably assured.

Rent expense for the three years ended December 31, 2013, was (in millions):



	2013		2012		2011
Office base rent	$	379.9	$	390.5	$	381.6
Less third party sublease rent	10.6		10.4		12.8
Net office rent	369.3		380.1		368.8
Equipment rent	33.1		36.3		42.7
	$	402.4	$	416.4	$	411.5

Future minimum lease payments under non-cancelable operating and capital leases, reduced by third party sublease rent receivable from existing non-cancelable subleases, are (in millions):



	Operating Leases						Capital Leases
	Gross Rent		Less Sublease Rent		Net Rent		Minimum Lease Payments
2014	$	380.4	$	8.6	$	371.8	$	22.8
2015	268.7		4.0		264.7		15.7
2016	195.3		1.6		193.7		8.6
2017	139.1		1.5		137.6		4.6
2018	111.2		0.4		110.8		3.3
Thereafter	302.9		—		302.9		2.4
	$	1,397.6	$	16.1	$	1,381.5

Total minimum lease payments							57.4
Less interest component							2.0
Present value of minimum lease payments							$	55.4

Property under capital lease and capital lease obligations as of December 31, 2013 and 2012 were (in millions):



	2013			2012
Property under capital lease:
Cost	$	134.0		$	126.3
Accumulated depreciation	(80.5		)	(71.3		)
	$	53.5		$	55.0

Capital lease obligations:
Current	$	22.2		$	23.4
Long-term	33.2			33.9
	$	55.4		$	57.3

Depreciation expense for property under capital lease was $26.4 million, $25.9 million and $25.0 million in 2013, 2012 and 2011, respectively.