Derivative Instruments (Details) - USD ($)
$ in Millions |
Sep. 30, 2016 |
Dec. 31, 2015 |
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
$ 250
|
$ 237
|
| Derivative Liabilities |
(259)
|
(281)
|
| Current Assets - Derivatives |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
152
|
157
|
| Deferred Charges and Other Assets - Other |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
98
|
80
|
| Current Liabilities - Derivatives |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Liabilities |
(91)
|
(106)
|
| Noncurrent Liabilities |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Liabilities |
(168)
|
(175)
|
| Commodity contracts | Current Assets - Derivatives |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
139
|
150
|
| Commodity contracts | Deferred Charges and Other Assets - Other |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
98
|
78
|
| Commodity contracts | Current Liabilities - Derivatives |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Liabilities |
(84)
|
(94)
|
| Commodity contracts | Noncurrent Liabilities |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Liabilities |
(50)
|
(37)
|
| FTRs | Current Assets - Derivatives |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
13
|
7
|
| FTRs | Deferred Charges and Other Assets - Other |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
0
|
1
|
| FTRs | Current Liabilities - Derivatives |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Liabilities |
(7)
|
(12)
|
| FTRs | Noncurrent Liabilities |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Liabilities |
0
|
(1)
|
| NUGs | Deferred Charges and Other Assets - Other |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Assets |
0
|
1
|
| NUGs | Noncurrent Liabilities |
|
|
| Fair value of derivatives instruments |
|
|
| Derivative Liabilities |
$ (118)
|
$ (137)
|