(11) Commitments

The following is a schedule of future minimum payments for firm transportation agreements, drilling and compression facility obligations, and leases that have remaining lease terms in excess of one year as of December 31, 2014 (in millions).


	Firm transportation		Gas processing, gathering and compression		Drilling rigs and frac services		Office and equipment
	(a)		(b)		(c)		(d)		Total
Year ending December 31:
2015	$	316		336		212		9		873
2016		593		237		161		9		1,000
2017		800		245		96		8		1,149
2018		867		244		—		6		1,117
2019		939		193		—		4		1,136
Thereafter		10,376		1,040		—		11		11,427
Total	$	13,891		2,295		469		47		16,702

(a) Firm Transportation

The Company has entered into firm transportation agreements with various pipelines in order to facilitate the delivery of its production to market. These contracts commit the Company to transport minimum daily natural gas or NGLs volumes at negotiated rates, or pay for any deficiencies at specified reservation fee rates. The amounts in this table represent minimum daily volumes at the reservation fee rate. The values in the table represent the gross amounts that the Company is committed to pay; however, the Company will record in the consolidated financial statements its proportionate share of costs based on its working interest.

(b) Gas Processing and Compression Service Commitments

The Company has entered into various long‑term gas processing agreements for certain of its production that will allow it to realize the value of its NGLs. The minimum payment obligations under the agreements are presented in the table.

The Company has various compressor service agreements with third parties that provide for payments based on volumes compressed and have minimum payment obligations which are presented in the table.

The values in the table represent the gross amounts that the Company is committed to pay; however, the Company will record in the consolidated financial statements its proportionate share of costs based on its working interest.

The Company has obligations under agreements with service providers to procure drilling rigs and compression and frac services. The values in the table represent the gross amounts that the Company is committed to pay; however, the Company will record in the consolidated financial statements its proportionate share of costs based on its working interest.

(d) Office and Equipment Leases

The Company leases various office space and equipment, as well as field equipment, under operating lease arrangements. Rental expense under operating leases was $1.1 million, $1.8 million, and $10.2 million for the years ended December 31, 2012, 2013, and 2014, respectively.