|
Business Segment Information (Operating Income is Derived from Revenues and Expenses Directly Associated with Each Segment) (Details) (USD $)
In Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
|
Jun. 30, 2011
|
Jun. 30, 2010
|
Jun. 30, 2011
|
Jun. 30, 2010
|
|
| Consolidated Revenues | $ 1,228.3 | $ 1,171.1 | $ 3,460.5 | $ 3,529.8 |
| Consolidated Operating Income | 163.3 | 139.2 | 562.5 | 542.6 |
|
Gas Transmission and Storage Operations [Member]
|
||||
| Unaffiliated | 200.5 | 185.6 | 413.9 | 380.1 |
| Intersegment | 33.0 | 31.7 | 75.0 | 93.8 |
| Total | 233.5 | 217.3 | 488.9 | 473.9 |
| Consolidated Operating Income | 84.7 | 74.9 | 203.2 | 200.8 |
|
Electric Operations [Member]
|
||||
| Unaffiliated | 350.8 | 342.3 | 699.6 | 662.1 |
| Intersegment | 0.2 | 0.2 | 0.4 | 0.4 |
| Total | 351.0 | 342.5 | 700.0 | 662.5 |
| Consolidated Operating Income | 39.8 | 49.6 | 83.0 | 94.7 |
|
Corporate and Other [Member]
|
||||
| Unaffiliated | 47.3 | 91.2 | 132.5 | 390.2 |
| Intersegment | 122.2 | 103.1 | 232.7 | 209.9 |
| Total | 169.5 | 194.3 | 365.2 | 600.1 |
| Consolidated Operating Income | (7.6) | (3.8) | (11.7) | (6.5) |
|
Gas Distribution Operations [Member]
|
||||
| Unaffiliated | 629.7 | 552.0 | 2,214.5 | 2,097.4 |
| Intersegment | 0.2 | 2.7 | 0.9 | 8.5 |
| Total | 629.9 | 554.7 | 2,215.4 | 2,105.9 |
| Consolidated Operating Income | 46.4 | 18.5 | 288.0 | 253.6 |
|
Elimination [Member]
|
||||
| Total | $ (155.6) | $ (137.7) | $ (309.0) | $ (312.6) |