|
Reconciliation of Segment Information, Total Assets (Details) (USD $)
In Thousands, unless otherwise specified |
Jun. 30, 2013
|
Dec. 31, 2012
|
Jun. 30, 2012
|
|---|---|---|---|
| Assets: | |||
| Assets | $ 12,752,928 | $ 12,670,909 | $ 12,597,896 |
| Items excluded from segment assets: | |||
| Recoverable Income Taxes | 1,930 | 0 | |
|
Total Reportable Business Segments
|
|||
| Assets: | |||
| Assets | 11,771,465 | 11,416,441 | |
|
Coal
|
|||
| Assets: | |||
| Assets | 5,600,934 | 5,445,502 | |
|
Gas
|
|||
| Assets: | |||
| Assets | 6,170,531 | 5,970,939 | |
|
All Other Segments [Member]
|
|||
| Assets: | |||
| Assets | 363,819 | 360,673 | |
|
Excludes Gas Segment [Member]
|
|||
| Items excluded from segment assets: | |||
| Cash and Other Investments | 45,905 | 186,611 | |
|
Intersegment Elimination [Member]
|
|||
| Assets: | |||
| Assets | 617,644 | 820,782 | |
| Items excluded from segment assets: | |||
| Recoverable Income Taxes | 1,930 | 0 | |
| Deferred Tax Assets | 531,707 | 588,722 | |
| Bond Issuance Costs | $ 38,102 | $ 45,449 |