Reconciliation of income and expenses (Details 4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss from discontinued operations	$ (276,102)	$ (263,419)	$ (294,138)	$ (593,404)
Loss from discontinued operations attributable to noncontrolling interest	(120,651)	(7,754)	(131,691)	(11,282)
Discontinued operations, held-for-sale or disposed of by sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenues	74,756	91,468	122,732	148,109
Operating expenses	443,756	505,487	513,526	1,086,781
Operating loss	(369,000)	(414,019)	(390,794)	(938,672)
Other income	183	385	387	2,459
Interest expense	832	434	1,753	517
Loss from discontinued operations before income taxes	(369,649)	(414,068)	(392,160)	(936,730)
Income taxes	(93,547)	(150,649)	(98,022)	(343,326)
Loss from discontinued operations	(276,102)	(263,419)	(294,138)	(593,404)
Loss from discontinued operations attributable to noncontrolling interest	(120,651)	(7,754)	(131,691)	(11,282)
Loss from discontinued operations attributable to the Company	(155,451)	(255,665)	(162,447)	(582,122)
Discontinued operations, held-for-sale or disposed of by sale [Member] | Refining [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pretax losses attributable to the Company	$ 244,000	$ 6,800	$ 253,900	$ 9,800