Long-Term Debt (Details) | Apr. 24, 2017 | Sep. 30, 2017USD ($) | Sep. 30, 2016USD ($) | Sep. 30, 2017USD ($) | Sep. 30, 2016USD ($) | Nov. 01, 2017USD ($) | Dec. 31, 2016USD ($) | May 05, 2016USD ($) |
Debt and Available Credit Facility | | | | | | | | |
Debt Instrument, Repurchased Face Amount | | $ 101,000,000 | $ 75,000,000 | $ 101,000,000 | $ 75,000,000 | | | |
Net Proceeds from Sale of Property, Plant, and Equipment | | | | | 388,000,000 | | | |
Total long-term debt, net | | 3,933,000,000 | | 3,933,000,000 | | | $ 3,789,000,000 | |
Repayments of Debt | | | | 118,000,000 | 407,000,000 | | | |
Debt Instrument, Repurchase Amount | | 157,000,000 | | 157,000,000 | | | | |
Payments of Debt Issuance Costs | | | | 21,000,000 | 24,000,000 | | | |
Gain/Loss on extinguishment of debt | | (24,000,000) | (26,000,000) | 16,000,000 | (384,000,000) | | | |
Deferred Finance Costs, Net | | $ 57,000,000 | | $ 57,000,000 | | | 77,000,000 | |
RatioOfFirstLienDebtToEBITDAX | | 0.66 | | 0.66 | | | | |
RatioOfDebtToEBITDAX | | 5.21 | | 5.21 | | | | |
Short-term Debt, net of debt issue costs | | $ (21,000,000) | | $ (21,000,000) | | | 0 | |
Debt Covenant Debt Repurchase Limit | | 885,000,000 | | $ 885,000,000 | | | | $ 350,000,000 |
Minimum | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Debt Covenant Debt to Earnings before Interest, Taxes, Depreciation, Amortization and Exploration Expense Ratio | 1 | | | 1 | | | | |
Maximum Covenant | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Debt Covenant Debt to Earnings before Interest, Taxes, Depreciation, Amortization and Exploration Expense Ratio | 3 | | | 4.5 | | | | |
RBL credit facility - due May 24, 2019 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Long-term debt, net | | 505,000,000 | | $ 505,000,000 | | | 370,000,000 | |
Gain/Loss on extinguishment of debt | | | 9,000,000 | | 9,000,000 | | | |
Write off of Deferred Debt Issuance Cost | | (1,000,000) | | (2,000,000) | | | | |
Deferred Finance Costs, Net | | 8,000,000 | | 8,000,000 | | | 10,000,000 | |
Borrowing capacity | | 1,437,000,000 | | 1,437,000,000 | | | | |
Letters of credit outstanding | | 19,000,000 | | 19,000,000 | | | | |
Remaining capacity | | 913,000,000 | | $ 913,000,000 | | | | |
RBL credit facility - due May 24, 2019 | London Interbank Offered Rate LIBOR | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Reference rate for variable interest rate | | | | LIBOR | | | | |
Senior Secured Term Loans and Senior Notes [Member] | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Deferred Finance Costs, Net | | 49,000,000 | | $ 49,000,000 | | | 67,000,000 | |
Senior secured term loan - due May 24, 2018 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Long-term debt, net | | $ 21,000,000 | | $ 21,000,000 | | | $ 21,000,000 | |
Debt instrument issuance as a percentage of the par value | | 99.00% | | 99.00% | | | | |
Effective interest rate (as a percent) | | 4.07% | | 4.07% | | | 3.50% | |
Deferred Finance Costs, Net | | $ 1,000,000 | | $ 1,000,000 | | | | |
Senior secured term loan - due May 24, 2018 | London Interbank Offered Rate LIBOR | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Reference rate for variable interest rate | | | | LIBOR | | | | |
Specified margin on reference rate (as a percent) | | | | 2.75% | | | | |
Senior secured term loan - due May 24, 2018 | London Interbank Offered Rate LIBOR | Minimum | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Reference rate for variable interest rate | | | | LIBOR | | | | |
Reference rate floor for variable interest rate (as a percent) | | 0.75% | | 0.75% | | | | |
Senior secured term loan - due April 30, 2019 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Long-term debt, net | | $ 8,000,000 | | $ 8,000,000 | | | $ 8,000,000 | |
Effective interest rate (as a percent) | | 4.82% | | 4.82% | | | 4.50% | |
Senior secured term loan - due April 30, 2019 | London Interbank Offered Rate LIBOR | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Specified margin on reference rate (as a percent) | | | | 3.50% | | | | |
Senior secured term loan - due April 30, 2019 | London Interbank Offered Rate LIBOR | Minimum | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Reference rate for variable interest rate | | | | LIBOR | | | | |
Senior secured term loan - due April 30, 2019 | London Interbank Offered Rate LIBOR | Maximum Covenant | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Reference rate for variable interest rate | | | | LIBOR | | | | |
Senior Secured Term Loan Due30 June2021 [Member] [Domain] | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Long-term debt, net | | $ 0 | | $ 0 | | | $ 580,000,000 | |
Senior Secured Term Loan Due30 June2021 [Member] [Domain] | London Interbank Offered Rate LIBOR | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Effective interest rate (as a percent) | | | | | | | 9.75% | |
Senior Secured Note Due 29 November 2024 [Member] | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Interest rate (as a percent) | | 8.00% | | 8.00% | | | | |
Long-term debt, net | | $ 500,000,000 | | $ 500,000,000 | | | $ 500,000,000 | |
Senior Secured Note Due 15 February 2025 [Member] | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Interest rate (as a percent) | | 8.00% | | 8.00% | | | | |
Long-term debt, net | | $ 1,000,000,000 | | $ 1,000,000,000 | | | 0 | |
Gain/Loss on extinguishment of debt | | | | (53,000,000) | | | | |
Write off of Deferred Debt Issuance Cost | | | | $ (30,000,000) | | | | |
Senior unsecured notes - due May 1, 2020 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Interest rate (as a percent) | | 9.375% | | 9.375% | | | | |
Long-term debt, net | | $ 1,200,000,000 | | $ 1,200,000,000 | | | 1,576,000,000 | |
Debt Instrument, Repurchase Amount | | $ 250,000,000 | | $ 250,000,000 | | | | |
Senior Unsecured Note Due1 September2022 [Member] | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Interest rate (as a percent) | | 7.75% | | 7.75% | | | | |
Long-term debt, net | | | | | | | 250,000,000 | |
Senior unsecured notes - due September 1, 2022 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Repayments of Debt | | | 47,000,000 | | | | | |
Debt Instrument, Repurchase Amount | | | 812,000,000 | | 812,000,000 | | | |
Gain/Loss on extinguishment of debt | | | (26,000,000) | $ (37,000,000) | (393,000,000) | | | |
Write off of Deferred Debt Issuance Cost | | | $ (1,000,000) | | $ (12,000,000) | | | |
Senior Notes [Member] | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Repayments of Debt | | $ 76,000,000 | | | | | | |
Gain/Loss on extinguishment of debt | | $ (24,000,000) | | | | | | |
Senior unsecured notes - due June 15, 2023 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Interest rate (as a percent) | | 6.375% | | 6.375% | | | | |
Long-term debt, net | | $ 519,000,000 | | $ 519,000,000 | | | 551,000,000 | |
EP Energy Global L L C [Member] | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Long-term debt, net | | 3,982,000,000 | | 3,982,000,000 | | | 3,856,000,000 | |
Debt, Long-term and Short-term, Combined Amount | | $ 4,003,000,000 | | 4,003,000,000 | | | $ 3,856,000,000 | |
EP Energy Global L L C [Member] | RBL credit facility - due May 24, 2019 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Repayments of Lines of Credit | | | | $ 111,000,000 | | | | |
EP Energy Global L L C [Member] | RBL credit facility - due May 24, 2019 | London Interbank Offered Rate LIBOR | Minimum | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Specified margin on reference rate (as a percent) | | | | 2.50% | | | | |
EP Energy Global L L C [Member] | RBL credit facility - due May 24, 2019 | London Interbank Offered Rate LIBOR | Maximum Covenant | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Specified margin on reference rate (as a percent) | | | | 3.50% | | | | |
EP Energy Global L L C [Member] | Senior secured term loan - due April 30, 2019 | London Interbank Offered Rate LIBOR | Minimum | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Reference rate floor for variable interest rate (as a percent) | | 1.00% | | 1.00% | | | | |
Subsequent Event [Member] | RBL credit facility - due May 24, 2019 | | | | | | | | |
Debt and Available Credit Facility | | | | | | | | |
Borrowing capacity | | | | | | $ 1,400,000,000 | | |