Fair Value Measurements Table - Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Millions | Jun. 30, 2015 | Dec. 31, 2014 |
Liabilities, Fair Value Disclosure, Recurring | $ (365) | $ (749) |
Fair Value, Inputs, Level 1 [Member] | | |
Liabilities, Fair Value Disclosure, Recurring | (243) | (551) |
Fair Value, Inputs, Level 2 [Member] | | |
Liabilities, Fair Value Disclosure, Recurring | (110) | (182) |
Level 3 [Member] | | |
Liabilities, Fair Value Disclosure, Recurring | (12) | (16) |
Commodity Derivatives - Natural Gas [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 2 | |
Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 1 [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | |
Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 2 [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 2 | |
Commodity Derivatives - Natural Gas [Member] | Level 3 [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | | |
Interest Rate Derivative Assets, at Fair Value | 1 | 3 |
Price Risk Derivative Assets, at Fair Value | 273 | 745 |
Assets, Fair Value Disclosure | 274 | 748 |
Interest Rate Derivative Liabilities, at Fair Value | (105) | (155) |
Embedded Derivative, Fair Value of Embedded Derivative Liability | (12) | (16) |
Price Risk Derivative Liabilities, at Fair Value | (248) | (578) |
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | | |
Interest Rate Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Assets, at Fair Value | 265 | 632 |
Assets, Fair Value Disclosure | 265 | 632 |
Interest Rate Derivative Liabilities, at Fair Value | 0 | 0 |
Embedded Derivative, Fair Value of Embedded Derivative Liability | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | (243) | (551) |
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | | |
Interest Rate Derivative Assets, at Fair Value | 1 | 3 |
Price Risk Derivative Assets, at Fair Value | 8 | 113 |
Assets, Fair Value Disclosure | 9 | 116 |
Interest Rate Derivative Liabilities, at Fair Value | (105) | (155) |
Embedded Derivative, Fair Value of Embedded Derivative Liability | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | (5) | (27) |
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | | |
Interest Rate Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Assets, Fair Value Disclosure | 0 | 0 |
Interest Rate Derivative Liabilities, at Fair Value | 0 | 0 |
Embedded Derivative, Fair Value of Embedded Derivative Liability | (12) | (16) |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Condensate [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 36 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Condensate [Member] | Fair Value, Inputs, Level 1 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Condensate [Member] | Fair Value, Inputs, Level 2 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 36 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Condensate [Member] | Level 3 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Basis Swaps IFERC/NYMEX [Member] | | |
Price Risk Derivative Assets, at Fair Value | 7 | 19 |
Price Risk Derivative Liabilities, at Fair Value | (7) | (18) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Swing Swaps IFERC [Member] | | |
Price Risk Derivative Assets, at Fair Value | 2 | 26 |
Price Risk Derivative Liabilities, at Fair Value | (2) | (25) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 213 | 566 |
Price Risk Derivative Liabilities, at Fair Value | (189) | (490) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 1 |
Price Risk Derivative Liabilities, at Fair Value | (1) | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 1 [Member] | Basis Swaps IFERC/NYMEX [Member] | | |
Price Risk Derivative Assets, at Fair Value | 7 | 19 |
Price Risk Derivative Liabilities, at Fair Value | (7) | (18) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 1 [Member] | Swing Swaps IFERC [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 1 |
Price Risk Derivative Liabilities, at Fair Value | (1) | (2) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 213 | 541 |
Price Risk Derivative Liabilities, at Fair Value | (189) | (490) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 1 [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 2 [Member] | Basis Swaps IFERC/NYMEX [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 2 [Member] | Swing Swaps IFERC [Member] | | |
Price Risk Derivative Assets, at Fair Value | 2 | 25 |
Price Risk Derivative Liabilities, at Fair Value | (1) | (23) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 25 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Fair Value, Inputs, Level 2 [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 1 |
Price Risk Derivative Liabilities, at Fair Value | (1) | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Level 3 [Member] | Basis Swaps IFERC/NYMEX [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Level 3 [Member] | Swing Swaps IFERC [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Level 3 [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Natural Gas [Member] | Level 3 [Member] | Forward Physical Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Refined Products [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | 6 | 21 |
Price Risk Derivative Liabilities, at Fair Value | (6) | (7) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Refined Products [Member] | Fair Value, Inputs, Level 1 [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | 6 | 21 |
Price Risk Derivative Liabilities, at Fair Value | (6) | (7) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Refined Products [Member] | Fair Value, Inputs, Level 2 [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Refined Products [Member] | Level 3 [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 4 | 3 |
Price Risk Derivative Liabilities, at Fair Value | (3) | (4) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 3 | |
Price Risk Derivative Liabilities, at Fair Value | (7) | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Put Option [Member] | | |
Price Risk Derivative Liabilities, at Fair Value | (4) | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Call Option [Member] | | |
Price Risk Derivative Assets, at Fair Value | 5 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 4 |
Price Risk Derivative Liabilities, at Fair Value | | (2) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 1 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 1 [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 3 | |
Price Risk Derivative Liabilities, at Fair Value | (7) | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 1 [Member] | Put Option [Member] | | |
Price Risk Derivative Liabilities, at Fair Value | (4) | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 1 [Member] | Call Option [Member] | | |
Price Risk Derivative Assets, at Fair Value | 5 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 1 [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 4 |
Price Risk Derivative Liabilities, at Fair Value | | (2) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 2 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 4 | 3 |
Price Risk Derivative Liabilities, at Fair Value | (3) | (4) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 2 [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | |
Price Risk Derivative Liabilities, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 2 [Member] | Put Option [Member] | | |
Price Risk Derivative Liabilities, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 2 [Member] | Call Option [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Fair Value, Inputs, Level 2 [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 0 |
Price Risk Derivative Liabilities, at Fair Value | | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Level 3 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Level 3 [Member] | Fixed Swaps/Futures [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | |
Price Risk Derivative Liabilities, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Level 3 [Member] | Put Option [Member] | | |
Price Risk Derivative Liabilities, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Level 3 [Member] | Call Option [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - Power [Member] | Level 3 [Member] | Future [Member] | | |
Price Risk Derivative Assets, at Fair Value | | 0 |
Price Risk Derivative Liabilities, at Fair Value | | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - NGLs [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 31 | 69 |
Price Risk Derivative Liabilities, at Fair Value | (29) | (32) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - NGLs [Member] | Fair Value, Inputs, Level 1 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 31 | 46 |
Price Risk Derivative Liabilities, at Fair Value | (29) | (32) |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - NGLs [Member] | Fair Value, Inputs, Level 2 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 23 |
Price Risk Derivative Liabilities, at Fair Value | 0 | 0 |
Fair Value, Measurements, Recurring [Member] | Commodity Derivatives - NGLs [Member] | Level 3 [Member] | Forward Swaps [Member] | | |
Price Risk Derivative Assets, at Fair Value | 0 | 0 |
Price Risk Derivative Liabilities, at Fair Value | $ 0 | $ 0 |