| **Consolidated Statements of Operations and Comprehensive Income - USD ($) $ in Millions**                                                                                                                                             | 12 Months Ended |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|
||
| **Operating Revenues**                                                                                                                                                                                                                 |                 |   |  |   |   |
| Regulated natural gas (1)                                                                                                                                                                                                              | [1]             | $ 1,131.6 |  | $ 1,371.7 | $ 1,470.0 |
| Nonregulated and other                                                                                                                                                                                                                 |                 | 10.1 |  | 11.4 | 9.5 |
| Related party revenue from Duke Energy (2)                                                                                                                                                                                             |                 | 7.0 | [2] |  |  |
| Total operating revenues                                                                                                                                                                                                               |                 | 1,148.7 |  | 1,383.1 | 1,479.5 |
| **Operating Expenses**                                                                                                                                                                                                                 |                 |   |  |   |   |
| Cost of natural gas (1)                                                                                                                                                                                                                | [1]             | 390.5 |  | 644.4 | 779.8 |
| Operations, maintenance and other                                                                                                                                                                                                      |                 | 352.9 |  | 304.8 | 279.9 |
| Depreciation and amortization                                                                                                                                                                                                          |                 | 137.3 |  | 128.7 | 119.0 |
| Property and other taxes                                                                                                                                                                                                               |                 | 42.6 |  | 42.4 | 37.7 |
| Total operating expenses                                                                                                                                                                                                               |                 | 923.3 |  | 1,120.3 | 1,216.4 |
| Operating Income                                                                                                                                                                                                                       |                 | 225.4 |  | 262.8 | 263.1 |
| **Other Income and Expense**                                                                                                                                                                                                           |                 |   |  |   |   |
| Equity in earnings of unconsolidated affiliates                                                                                                                                                                                        |                 | 28.6 |  | 34.5 | 32.8 |
| Gain on sale of unconsolidated affiliates                                                                                                                                                                                              |                 | 132.8 |  | 0.0 | 0.0 |
| Other expense, net                                                                                                                                                                                                                     |                 | 0.8 |  | 1.5 | 2.6 |
| Total other income and expense                                                                                                                                                                                                         |                 | 160.6 |  | 33.0 | 30.2 |
| Interest Expense                                                                                                                                                                                                                       |                 | 68.6 |  | 68.6 | 54.7 |
| Income Before Income Taxes                                                                                                                                                                                                             |                 | 317.4 |  | 227.2 | 238.6 |
| Income Tax Expense                                                                                                                                                                                                                     |                 | 124.2 |  | 90.2 | 94.8 |
| Net Income                                                                                                                                                                                                                             |                 | 193.2 |  | 137.0 | 143.8 |
| Unrealized (loss) gain from hedging activities, net of tax of ($2.5), ($1.0) and $0.2 for the years ended October 31, 2016, 2015 and 2014, respectively                                                                                |                 | (2.8) |  | (1.6) | 0.3 |
| Reclassification adjustment of realized loss (gain) from hedging activities of equity method investments included in net income, net of tax of $2.0, $0.7 and ($0.2) for the years ended October 31, 2016, 2015 and 2014, respectively |                 | 3.4 |  | 1.0 | (0.3) |
| Other Comprehensive Income (Loss), net of tax                                                                                                                                                                                          |                 | 0.6 |  | (0.6) | 0.0 |
| Comprehensive Income                                                                                                                                                                                                                   |                 | $ 193.8 |  | $ 136.4 | $ 143.8 |
|                                                                                                                                                                                                                                        |
| [1]See Note 11 for amounts attributable to investments in unconsolidated affiliates.[2]See Note 14 for details on related party transactions with Duke Energy.                                                                         |

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.
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Total costs of sales and operating expenses for the period.
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Amount of gain (loss) on sale or disposal of an equity method investment.
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Revenue derived from the regulated (by a federal, state, or local government or agency) generation, transmission and distribution of [natural] gas.
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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.
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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.
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Amount of the cost of borrowed funds accounted for as interest expense.
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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.
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The aggregate amount of income or expense from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business).
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The net result for the period of deducting operating expenses from operating revenues.
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Amount after tax of other comprehensive income (loss) attributable to parent entity.
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Amount before tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).
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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).
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Amount of expense related to nonoperating activities, classified as other.
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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.
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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.
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All taxes not related to income of the entity or excise or sales taxes levied on the revenue of the entity that are not reported elsewhere. These taxes could include production, real estate, personal property, and pump tax.
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The amount of unregulated operating revenues recognized during the period.
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Amount of operating expense for depreciation and amortization of regulated operation.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688
+ Details**Name:**us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of operating expense for purchased gas and petroleum of regulated operation.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688
+ Details**Name:**us-gaap_UtilitiesOperatingExpenseGasAndPetroleumPurchased**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of operating expenses for the period that are associated with the utility's normal revenue producing operation; including selling, general, and administrative expenses, costs incurred for routine plant repairs and maintenance, and operations.
+ References
No definition available.
+ Details**Name:**us-gaap_UtilitiesOperatingExpenseMaintenanceOperationsAndOtherCostsAndExpenses**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |