Premises and Equipment and Other Assets

Premises and Equipment

Premises and equipment are carried at cost, less accumulated depreciation and amortization. As of December 31, 2016 and 2015, the amounts were as follows:



	December 31,
	2016							2015
(Dollars in millions)	Cost		Accumulated Depreciation and Amortization			Net Book Value		Cost		Accumulated Depreciation and Amortization			Net Book Value
Land	$	120	$	—		$	120	$	140	$	—		$	140
Premises	473		(275		)	198		599		(341		)	258
Leasehold improvements	405		(255		)	150		357		(239		)	118
Furniture, fixtures and equipment	637		(514		)	123		688		(560		)	128
Total	$	1,635	$	(1,044	)	$	591	$	1,784	$	(1,140	)	$	644

Rental, depreciation and amortization expenses were as follows:



	For the Years Ended December 31,
(Dollars in millions)	2016		2015		2014
Rental expense of premises	$	128	$	134	$	120
Less: rental income	15		24		9
Net rental expense	$	113	$	110	$	111
Depreciation and amortization of premises and equipment	$	92	$	99	$	105

Future minimum lease payments at December 31, 2016 were as follows:



(Dollars in millions)	2016
Years ending December 31,:
2017	$	148
2018	135
2019	113
2020	101
2021	86
Thereafter	398
Total minimum lease payments	$	981
Minimum rental income due in the future under subleases	$	10

The Company's leases are for land, branch or office space. A majority of the leases provide for the payment of taxes, maintenance, insurance, and certain other expenses applicable to the leased premises. Many of the leases contain extension provisions and escalation clauses. These leases are generally renewable and may in certain cases contain provisions and options to expand or contract space, renew or terminate the lease or purchase the leased premises at predetermined contractual dates. In addition, escalation clauses may exist, which are tied to either a predetermined rate or may change based on a specified percentage increase or the Consumer Price Index.

At December 31, 2016 and 2015, the Company had a liability of $4 million and $6 million, respectively, for asset retirement obligations. These obligations include environmental remediation on buildings and the removal of leasehold improvements from leased premises to be vacated in cases where management has sufficient information to estimate the obligation's fair value.

Other Assets

The following table shows the balances of other assets as of December 31, 2016 and 2015.



(Dollars in millions)	December 31, 2016		December 31, 2015
Other investments	$	3,468	$	3,171
Software	441		370
Intangible assets	246		206
OREO	3		21
Other	4,338		2,769
Total other assets	$	8,496	$	6,537