FAIR VALUE MEASUREMENTS (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions | Jun. 30, 2017 | Sep. 30, 2016 | Jun. 30, 2016 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | $ (5.6) | $ (7.6) | |
Derivative liability | 4.4 | 4.9 | |
Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.3) | (0.7) | $ (3.1) |
Derivative asset | 22.8 | 25.8 | 25.5 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.3) | (1.6) | 0 |
Derivative liability | 0 | 0.2 | 0.6 |
Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 2.1 | 5.1 | |
Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 20 | 22.4 | 24.6 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 1.3 | 1.6 | 0 |
Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 7.9 | 7.4 | |
Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4.1 | 4.1 | 4 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0.2 | 0.6 |
Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | |
Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
US stock/bond mutual funds | Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | 0 | 0 |
Derivative asset | 22.1 | 20.9 | 20.4 |
US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 18 | 16.8 | 16.4 |
US stock/bond mutual funds | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4.1 | 4.1 | 4 |
US stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
NYMEX/ICE natural gas contracts | Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.3) | (0.4) | (3.1) |
Derivative asset | 0.6 | 4.9 | 5.1 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.3) | (1.6) | |
Derivative liability | 0 | 0 | |
NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 1.9 | 5.3 | 8.2 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 1.3 | 1.6 | |
NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | |
NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | |
Gasoline and heating oil contracts | Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | (0.3) | |
Derivative asset | 0.1 | 0 | |
Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.1 | 0.3 | |
Gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
OTCBB natural gas contracts | Laclede Gas | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | 0 | 0 |
Derivative liability | | 0.2 | 0.6 |
OTCBB natural gas contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
OTCBB natural gas contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0.2 | 0.6 |
OTCBB natural gas contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Interest rate swaps | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | | |
Derivative liability | (0.6) | | |
Interest rate swaps | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | | |
Interest rate swaps | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | (0.6) | | |
Interest rate swaps | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | | |
Other | Interest rate swaps | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | 0 | 0 |
Derivative liability | | 3 | 4 |
Other | Interest rate swaps | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Other | Interest rate swaps | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 3 | 4 |
Other | Interest rate swaps | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Gas Utility | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.3) | (0.7) | (3.1) |
Derivative asset | 22.8 | 25.9 | 25.5 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | (1.6) | 0 |
Derivative liability | | 0.2 | 0.6 |
Gas Utility | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 20 | 22.5 | 24.6 |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 1.6 | 0 |
Gas Utility | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4.1 | 4.1 | 4 |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0.2 | 0.6 |
Gas Utility | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Gas Utility | US stock/bond mutual funds | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | 0 | 0 |
Derivative asset | 22.1 | 20.9 | 20.4 |
Gas Utility | US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 18 | 16.8 | 16.4 |
Gas Utility | US stock/bond mutual funds | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4.1 | 4.1 | 4 |
Gas Utility | US stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
Gas Utility | NYMEX/ICE natural gas contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.3) | (0.4) | (3.1) |
Derivative asset | 0.6 | 4.9 | 5.1 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.3) | (1.6) | |
Derivative liability | 0 | 0 | |
Gas Utility | NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 1.9 | 5.3 | 8.2 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 1.3 | 1.6 | |
Gas Utility | NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | |
Gas Utility | NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | |
Gas Utility | Gasoline and heating oil contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | (0.3) | |
Derivative asset | 0.1 | 0.1 | |
Gas Utility | Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.1 | 0.4 | |
Gas Utility | Gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
Gas Utility | Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
Gas Utility | OTCBB natural gas contracts | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | 0 | 0 |
Derivative liability | | 0.2 | 0.6 |
Gas Utility | OTCBB natural gas contracts | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Gas Utility | OTCBB natural gas contracts | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0.2 | 0.6 |
Gas Utility | OTCBB natural gas contracts | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Gas Marketing | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (5.6) | | |
Derivative asset | 29.9 | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | | (9.5) |
Derivative liability | | | 7.5 |
Gas Marketing | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 21.5 | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 6.5 |
Gas Marketing | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 13.4 | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 10.5 |
Gas Marketing | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.6 | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
Gas Marketing | US stock/bond mutual funds | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | | (5) | (9.3) |
Derivative asset | | 34.3 | 32 |
Gas Marketing | US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 22.9 | 25.2 |
Gas Marketing | US stock/bond mutual funds | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 16.2 | 15.8 |
Gas Marketing | US stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 0.2 | 0.3 |
Gas Marketing | NYMEX/ICE natural gas contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (2.6) | (3.4) | (5.6) |
Derivative asset | 2.1 | 0.4 | 0.5 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (2.6) | (5.1) | (9) |
Derivative liability | 0 | 0 | 0 |
Gas Marketing | NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 1.5 | 0.4 | 0.6 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0.8 | 3.5 | 6.5 |
Gas Marketing | NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 3.2 | 3.4 | 5.5 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 1.8 | 1.6 | 2.5 |
Gas Marketing | NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Marketing | Natural gas commodity contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.7) | (0.9) | (0.6) |
Derivative asset | 5 | 8 | 6 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.7) | (0.9) | (0.5) |
Derivative liability | 5 | 1.7 | 2.9 |
Gas Marketing | Natural gas commodity contracts | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Marketing | Natural gas commodity contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 6.1 | 8.7 | 6.3 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 6.7 | 2.6 | 3.4 |
Gas Marketing | Natural gas commodity contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.6 | 0.2 | 0.3 |
LIABILITIES | | | |
Derivative liability before netting adjustment | $ 0 | $ 0 | $ 0 |