Income Taxes (Schedule Of Reasons Behind Differences In Computation Of Total Income Taxes) (Details) - USD ($)
$ in Millions |
12 Months Ended |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Schedule of Reasons Behind Differences in Computation of Total Income Taxes [Line Items] |
|
|
|
| Book income before income taxes |
$ 554.1
|
|
|
| Tax expense at statutory federal income tax rate, value |
$ 193.9
|
|
|
| Tax expense at statutory federal income tax rate, rate |
35.00%
|
|
|
| State income taxes, net of federal income tax benefit, value |
$ 2.0
|
|
|
| State income taxes, net of federal income tax benefit, rate |
0.40%
|
|
|
| Income not subject to income tax at the partnership level, rate |
$ (170.6)
|
|
|
| Income not subject to income tax at the partnership level, value |
(30.90%)
|
|
|
| AFUDC-Equity, value |
$ (0.3)
|
|
|
| AFUDC-Equity, rate |
(0.00%)
|
|
|
| Other, net, value |
$ (1.1)
|
|
|
| Other net, rate |
(0.20%)
|
|
|
| Total Income Taxes |
$ 23.9
|
|
|
| Total Income Taxes, rate |
4.30%
|
|
|
| Predecessor |
|
|
|
| Schedule of Reasons Behind Differences in Computation of Total Income Taxes [Line Items] |
|
|
|
| Book income before income taxes |
|
$ 435.5
|
$ 419.3
|
| Tax expense at statutory federal income tax rate, value |
|
$ 152.4
|
$ 146.8
|
| Tax expense at statutory federal income tax rate, rate |
|
35.00%
|
35.00%
|
| State income taxes, net of federal income tax benefit, value |
|
$ 17.9
|
$ 8.2
|
| State income taxes, net of federal income tax benefit, rate |
|
4.10%
|
1.90%
|
| Income not subject to income tax at the partnership level, rate |
|
$ 0.0
|
$ 0.0
|
| Income not subject to income tax at the partnership level, value |
|
(0.00%)
|
(0.00%)
|
| AFUDC-Equity, value |
|
$ (3.8)
|
$ (2.4)
|
| AFUDC-Equity, rate |
|
(0.90%)
|
(0.60%)
|
| Other, net, value |
|
$ (0.1)
|
$ (0.2)
|
| Other net, rate |
|
0.00%
|
0.00%
|
| Total Income Taxes |
|
$ 166.4
|
$ 152.4
|
| Total Income Taxes, rate |
|
38.20%
|
36.30%
|