Condensed Consolidating Financial Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Condensed Consolidating Financial Information
Operating revenues	$ 2,043us-gaap_Revenues	$ 2,339us-gaap_Revenues
Cost and expenses	1,421us-gaap_CostsAndExpenses	1,599us-gaap_CostsAndExpenses
Loss on impairment	(936)us-gaap_AssetImpairmentCharges	(65)us-gaap_AssetImpairmentCharges
Loss on disposal of assets, net	(7)us-gaap_GainLossOnDispositionOfAssets	(3)us-gaap_GainLossOnDispositionOfAssets
Operating income (loss)	(321)us-gaap_OperatingIncomeLoss	672us-gaap_OperatingIncomeLoss
Other income (expense), net
Interest income (expense), net	(110)us-gaap_InterestIncomeExpenseNet	(116)us-gaap_InterestIncomeExpenseNet
Other, net	47	(2)
Total other income (expense), net	(63)us-gaap_NonoperatingIncomeExpense	(118)us-gaap_NonoperatingIncomeExpense
Income (loss) from continuing operations before income tax expense	(384)	554
Income tax expense	83us-gaap_IncomeTaxExpenseBenefit	80us-gaap_IncomeTaxExpenseBenefit
Income (loss) from continuing operations	(467)	474
Gain (loss) from discontinued operations, net of tax	(2)	(8)
Net income (loss)	(469)us-gaap_ProfitLoss	466us-gaap_ProfitLoss
Net loss attributable to noncontrolling interest	14	10
Net income (loss) attributable to controlling interest	(483)us-gaap_NetIncomeLoss	456us-gaap_NetIncomeLoss
Other comprehensive income (loss) before income taxes	(8)	(1)
Income taxes related to other comprehensive income (loss)	(2)us-gaap_OtherComprehensiveIncomeLossTax
Other comprehensive income (loss), net of income taxes	(10)	(1)
Total comprehensive income (loss)	(479)	465
Total comprehensive income attributable to noncontrolling interest	14	10
Total comprehensive income (loss) attributable to controlling interest	(493)us-gaap_ComprehensiveIncomeNetOfTax	455us-gaap_ComprehensiveIncomeNetOfTax
Reportable Entity \| Parent Guarantor
Condensed Consolidating Financial Information
Cost and expenses	4	9
Operating income (loss)	(4)	(9)
Other income (expense), net
Interest income (expense), net		6
Equity in earnings	(479)	459
Total other income (expense), net	(479)	465
Income (loss) from continuing operations before income tax expense	(483)	456
Income (loss) from continuing operations	(483)	456
Net income (loss)	(483)	456
Net income (loss) attributable to controlling interest	(483)	456
Other comprehensive income (loss) before income taxes	(2)	(2)
Other comprehensive income (loss), net of income taxes	(2)	(2)
Total comprehensive income (loss)	(485)	454
Total comprehensive income (loss) attributable to controlling interest	(485)	454
Reportable Entity \| Subsidiary Issuer
Condensed Consolidating Financial Information
Cost and expenses	2	1
Operating income (loss)	(2)	(1)
Other income (expense), net
Interest income (expense), net	(161)	139
Equity in earnings	(268)	287
Other, net	39	1
Total other income (expense), net	(390)	427
Income (loss) from continuing operations before income tax expense	(392)	426
Income (loss) from continuing operations	(392)	426
Gain (loss) from discontinued operations, net of tax	1	4
Net income (loss)	(391)	430
Net income (loss) attributable to controlling interest	(391)	430
Other comprehensive income (loss) before income taxes	(9)	(6)
Other comprehensive income (loss), net of income taxes	(9)	(6)
Total comprehensive income (loss)	(400)	424
Total comprehensive income (loss) attributable to controlling interest	(400)	424
Reportable Entity \| Other Subsidiaries
Condensed Consolidating Financial Information
Operating revenues	2,043	2,343
Cost and expenses	1,415	1,593
Loss on impairment	(936)	(65)
Loss on disposal of assets, net	(7)	(3)
Operating income (loss)	(315)	682
Other income (expense), net
Interest income (expense), net	51	(261)
Other, net	8	(3)
Total other income (expense), net	59	(264)
Income (loss) from continuing operations before income tax expense	(256)	418
Income tax expense	83	80
Income (loss) from continuing operations	(339)	338
Gain (loss) from discontinued operations, net of tax	(3)	(12)
Net income (loss)	(342)	326
Net loss attributable to noncontrolling interest	14	10
Net income (loss) attributable to controlling interest	(356)	316
Other comprehensive income (loss) before income taxes	3	7
Income taxes related to other comprehensive income (loss)	(2)
Other comprehensive income (loss), net of income taxes	1	7
Total comprehensive income (loss)	(341)	333
Total comprehensive income attributable to noncontrolling interest	14	10
Total comprehensive income (loss) attributable to controlling interest	(355)	323
Consolidating adjustments
Condensed Consolidating Financial Information
Operating revenues		(4)
Cost and expenses		(4)
Other income (expense), net
Equity in earnings	747	(746)
Total other income (expense), net	747	(746)
Income (loss) from continuing operations before income tax expense	747	(746)
Income (loss) from continuing operations	747	(746)
Net income (loss)	747	(746)
Net income (loss) attributable to controlling interest	747	(746)
Total comprehensive income (loss)	747	(746)
Total comprehensive income (loss) attributable to controlling interest	$ 747	$ (746)

The net amount of other nonoperating income and expense, which does not qualify for separate disclosure on the income statement under materiality guidelines including the gains and losses included in earnings resulting from the extinguishment of debt.

No definition available.