|
Fair Value (Details 1) (USD $)
In Millions, unless otherwise specified
|
3 Months Ended |
9 Months Ended |
|
Sep. 30, 2012
|
Sep. 30, 2011
|
Sep. 30, 2012
|
Sep. 30, 2011
|
| Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis |
|
|
|
|
| Beginning Balance |
$ 57 |
$ 65 |
$ 44 |
$ 59 |
| Transfers into Level 3 |
0 |
(7) |
29 |
(4) |
| Transfer out of Level 3 |
0 |
(42) |
(2) |
(24) |
| Total gains: [Abstract] |
|
|
|
|
| Included in earnings |
(30) |
29 |
15 |
39 |
| Recorded in regulatory assets/liabilities |
7 |
0 |
12 |
3 |
| Purchases issuances and settlements [Abstract] |
|
|
|
|
| Purchases |
0 |
0 |
1 |
1 |
| Settlements |
(48) |
(36) |
(113) |
(65) |
| Ending Balance |
(14) |
9 |
(14) |
9 |
| The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period |
(37) |
11 |
4 |
24 |
|
Natural Gas [Member]
|
|
|
|
|
| Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis |
|
|
|
|
| Beginning Balance |
2 |
1 |
6 |
1 |
| Transfers into Level 3 |
0 |
(1) |
1 |
0 |
| Transfer out of Level 3 |
0 |
0 |
(2) |
1 |
| Total gains: [Abstract] |
|
|
|
|
| Included in earnings |
(43) |
6 |
(38) |
3 |
| Recorded in regulatory assets/liabilities |
0 |
0 |
0 |
0 |
| Purchases issuances and settlements [Abstract] |
|
|
|
|
| Purchases |
0 |
0 |
0 |
0 |
| Settlements |
(3) |
(1) |
(11) |
0 |
| Ending Balance |
(44) |
5 |
(44) |
5 |
| The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period |
(43) |
6 |
(39) |
5 |
|
Electricity [Member]
|
|
|
|
|
| Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis |
|
|
|
|
| Beginning Balance |
50 |
57 |
32 |
54 |
| Transfers into Level 3 |
0 |
(6) |
28 |
(4) |
| Transfer out of Level 3 |
0 |
(42) |
0 |
(25) |
| Total gains: [Abstract] |
|
|
|
|
| Included in earnings |
12 |
23 |
53 |
34 |
| Recorded in regulatory assets/liabilities |
0 |
0 |
0 |
0 |
| Purchases issuances and settlements [Abstract] |
|
|
|
|
| Purchases |
0 |
0 |
1 |
1 |
| Settlements |
(38) |
(35) |
(90) |
(63) |
| Ending Balance |
24 |
(3) |
24 |
(3) |
| The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period |
5 |
5 |
43 |
17 |
|
Other Credit Derivatives [Member]
|
|
|
|
|
| Fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis |
|
|
|
|
| Beginning Balance |
5 |
7 |
6 |
4 |
| Transfers into Level 3 |
0 |
0 |
0 |
0 |
| Transfer out of Level 3 |
0 |
0 |
0 |
0 |
| Total gains: [Abstract] |
|
|
|
|
| Included in earnings |
1 |
0 |
0 |
2 |
| Recorded in regulatory assets/liabilities |
7 |
0 |
12 |
3 |
| Purchases issuances and settlements [Abstract] |
|
|
|
|
| Purchases |
0 |
0 |
0 |
0 |
| Settlements |
(7) |
0 |
(12) |
(2) |
| Ending Balance |
6 |
7 |
6 |
7 |
| The amount of total gains (losses) included in net income attributed to the change in unrealized gains or losses related to assets still held at the end of the period |
$ 1 |
$ 0 |
$ 0 |
$ 2 |