Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Significant Accounting Policies

Schedule of revenue from supply shortfalls

Revenue recorded for the shortfall between actual production volumes and the MVC are as follows (in millions):

	Texas		Oklahoma		Crude and Condensate		Total
Year Ended December 31, 2016
Midstream services	$	1.9	$	9.5	$	—	$	11.4
Midstream services - related parties		26.4		10.8		9.0		46.2
Total	$	28.3	$	20.3	$	9.0	$	57.6
Year Ended December 31, 2015
Midstream services	$	0.5	$	—	$	—	$	0.5
Midstream services - related parties		3.8		20.1		0.5		24.4
Total	$	4.3	$	20.1	$	0.5	$	24.9

Property, Plant, and Equipment

The components of property, plant and equipment are as follows (in millions):

	Year Ended December 31,
	2016		2015
Transmission assets	$	1,191.7	$	1,285.1
Gathering systems		3,530.9		2,999.2
Gas processing plants		3,163.0		2,673.7
Other property and equipment		149.5		135.9
Construction in process		345.7		330.5
Property, plant and equipment		8,380.8		7,424.4
Accumulated depreciation		(2,124.1)		(1,757.6)
Property, plant and equipment, net	$	6,256.7	$	5,666.8

Schedule Of Property, Plant, and Equipment Useful Lives

Depreciation is calculated using the straight-line method based on the estimated useful life of each asset, as follows:

	Useful Lives
Transmission assets	20 - 25 years
Gathering systems	20 - 25 years
Gas processing plants	20 - 25 years
Other property and equipment	3 - 15 years