Variable Interest Entities (Tables)

6 Months Ended

Jun. 30, 2011

Variable Interest Entities

Consolidated assets and liabilities attributable to VIEs, excluding intercompany balances

	As of June 30, 2011
	MarkWest Liberty Midstream		MarkWest Pioneer		Total
ASSETS
Cash and cash equivalents	$	20,491	$	2,372	$	22,863
Receivables, net	11,311		1,328		12,639
Inventories	12,511		—		12,511
Other current assets	746		—		746
Property, plant and equipment, net of accumulated depreciation of $43,944 and $12,425, respectively	811,555		143,921		955,476
Restricted cash	28,100		—		28,100
Other long-term assets	267		103		370
Total assets	$	884,981	$	147,724	$	1,032,705
LIABILITIES
Accounts payable	$	14,532	$	35	$	14,567
Accrued liabilities	48,177		901		49,078
Other long-term liabilities	90		71		161
Total liabilities	$	62,799	$	1,007	$	63,806

	As of December 31, 2010
	MarkWest Liberty Midstream		MarkWest Pioneer		Total
ASSETS
Cash and cash equivalents	$	—	$	2,913	$	2,913
Receivables, net	42,181		1,602		43,783
Inventories	8,431		—		8,431
Other current assets	271		1		272
Property, plant and equipment, net of accumulated depreciation of $28,869 and $9,300, respectively	664,778		147,039		811,817
Restricted cash	28,001		—		28,001
Other long-term assets	281		102		383
Total assets	$	743,943	$	151,657	$	895,600
LIABILITIES
Accounts payable	$	5,945	$	—	$	5,945
Accrued liabilities	63,450		1,263		64,713
Other long-term liabilities	86		68		154
Total liabilities	$	69,481	$	1,331	$	70,812