Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($)
$ in Millions |
Dec. 31, 2015 |
Dec. 31, 2014 |
| Property, Plant and Equipment [Line Items] |
|
|
| Property Plant and Equipment |
$ 8,930.9
|
$ 7,931.6
|
| Accumulated Depreciation and Amortization |
(2,960.1)
|
(2,971.4)
|
| Net Property, Plant and Equipment |
5,970.8
|
4,960.2
|
| Pipeline and Other Transmission Assets |
|
|
| Property, Plant and Equipment [Line Items] |
|
|
| Property Plant and Equipment |
6,120.0
|
5,328.2
|
| Storage Facilities |
|
|
| Property, Plant and Equipment [Line Items] |
|
|
| Property Plant and Equipment |
1,370.1
|
1,326.5
|
| Gas Stored Base Gas |
|
|
| Property, Plant and Equipment [Line Items] |
|
|
| Property Plant and Equipment |
299.5
|
299.5
|
| Gas Gathering and Processing Equipment |
|
|
| Property, Plant and Equipment [Line Items] |
|
|
| Property Plant and Equipment |
370.2
|
263.3
|
| Construction Work In Process |
|
|
| Property, Plant and Equipment [Line Items] |
|
|
| Property Plant and Equipment |
463.5
|
454.2
|
| General Plant, Software, and Other Assets |
|
|
| Property, Plant and Equipment [Line Items] |
|
|
| Property Plant and Equipment |
$ 307.6
|
$ 259.9
|