Transactions With Affiliates (Schedule of Affiliated Transactions) (Details) - Related Party Transaction [Domain] - USD ($)
$ in Millions |
3 Months Ended |
6 Months Ended |
|
Jun. 30, 2015 |
Jun. 30, 2014 |
Jun. 30, 2015 |
Jun. 30, 2014 |
Dec. 31, 2014 |
| Related Party Transaction [Line Items] |
|
|
|
|
|
| Transportation revenues-affiliated |
$ 18.4
|
|
$ 47.1
|
|
|
| Storage revenues |
12.9
|
|
26.2
|
|
|
| Other revenues |
0.1
|
|
0.2
|
|
|
| Operation and maintenance-affiliated |
38.6
|
|
74.7
|
|
|
| Interest expense |
6.3
|
|
17.7
|
|
|
| Interest income |
2.3
|
|
3.3
|
|
|
| Accounts receivable |
656.7
|
|
656.7
|
|
|
| Current portion of long-term debt-affiliated |
0.0
|
|
0.0
|
|
|
| Short-term Debt |
20.0
|
|
20.0
|
|
|
| Short-term borrowings-affiliated |
67.1
|
|
67.1
|
|
|
| Accounts payable |
41.5
|
|
41.5
|
|
|
| Long-term debt |
$ 630.9
|
|
$ 630.9
|
|
|
| Predecessor [Member] |
|
|
|
|
|
| Related Party Transaction [Line Items] |
|
|
|
|
|
| Transportation revenues-affiliated |
|
$ 18.9
|
|
$ 47.5
|
|
| Storage revenues |
|
13.2
|
|
26.9
|
|
| Other revenues |
|
0.1
|
|
0.2
|
|
| Operation and maintenance-affiliated |
|
29.5
|
|
57.8
|
|
| Interest expense |
|
12.6
|
|
24.7
|
|
| Interest income |
|
$ 0.1
|
|
$ 0.2
|
|
| Accounts receivable |
|
|
|
|
$ 153.8
|
| Current portion of long-term debt-affiliated |
|
|
|
|
115.9
|
| Short-term Debt |
|
|
|
|
0.0
|
| Short-term borrowings-affiliated |
|
|
|
|
247.3
|
| Accounts payable |
|
|
|
|
49.9
|
| Long-term debt |
|
|
|
|
$ 1,472.8
|