FAIR VALUE MEASUREMENTS (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions | Mar. 31, 2016 | Sep. 30, 2015 | Mar. 31, 2015 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | $ (20) | | |
Derivative liability | 10.7 | | |
Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | $ (1.3) | $ (0.6) |
Derivative asset | 20.2 | 19.5 | 20.3 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (13.7) | (16.7) | (15.1) |
Derivative liability | 6 | 5.9 | 14.5 |
Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 15.8 | | |
Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 16.2 | 16.8 | 17 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 13.7 | 16.7 | 15.1 |
Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 14.9 | | |
Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4 | 4 | 3.9 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 6 | 5.9 | 14.5 |
Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 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 |
U. S. stock/bond mutual funds | Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | 0 | 0 |
Derivative asset | 20.2 | 19.5 | 20.3 |
U. S. stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 16.2 | 15.5 | 16.4 |
U. S. stock/bond mutual funds | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4 | 4 | 3.9 |
U. S. stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
Gasoline and heating oil contracts | Laclede Gas | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.2) | | (1) |
Derivative liability | 0 | | 0 |
Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0.2 | | 1 |
Gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | | 0 |
Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | | 0 |
NYMEX/ICE natural gas contracts | Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | | (1.3) | (0.6) |
Derivative asset | | 0 | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (13.5) | (16.4) | (14.1) |
Derivative liability | 0 | 0 | 0 |
Fair Value Assets Measured On Recurring Basis NYMEX Natural Gas Contracts Derivative Assets | | | 0 |
NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 1.3 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 13.5 | 16.4 | 14.1 |
Fair Value Assets Measured On Recurring Basis NYMEX Natural Gas Contracts Derivative Assets | | | 0.6 |
NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 0 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Fair Value Assets Measured On Recurring Basis NYMEX Natural Gas Contracts Derivative Assets | | | 0 |
NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 0 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Fair Value Assets Measured On Recurring Basis NYMEX Natural Gas Contracts Derivative Assets | | | 0 |
OTCBB natural gas contracts | Laclede Gas | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | 0 | 0 |
Derivative liability | 6 | 5.9 | 14.5 |
OTCBB natural gas contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
OTCBB natural gas contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 6 | 5.9 | 14.5 |
OTCBB natural gas contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
NYMEX gasoline and heating oil contracts | Laclede Gas | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | (0.3) | |
Derivative liability | | 0 | |
NYMEX gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0.3 | |
NYMEX gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | |
NYMEX gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | |
Interest rate swaps | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | | |
Derivative liability | 1.8 | | |
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 | 1.8 | | |
Interest rate swaps | Significant Observable Inputs (Level 2) | Alagasco | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 2.9 | | |
Interest rate swaps | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | | |
Gas Utility | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | (1.3) | (0.6) |
Derivative asset | 20.3 | 19.5 | 20.3 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (13.7) | (16.7) | (15.1) |
Derivative liability | 6 | 5.9 | 17.4 |
Gas Utility | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 16.3 | 16.8 | 17 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 13.7 | 16.7 | 15.1 |
Gas Utility | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4 | 4 | 3.9 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 6 | 5.9 | 17.4 |
Gas Utility | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Utility | U. S. stock/bond mutual funds | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | 0 | 0 |
Derivative asset | 20.2 | 19.5 | 20.3 |
Gas Utility | U. S. stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 16.2 | 15.5 | 16.4 |
Gas Utility | U. S. stock/bond mutual funds | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4 | 4 | 3.9 |
Gas Utility | U. S. stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
Gas Utility | Gasoline and heating oil contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | | |
Derivative asset | 0.1 | | |
Gas Utility | Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.1 | | |
Gas Utility | Gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | | |
Gas Utility | Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | | |
Gas Utility | NYMEX/ICE natural gas contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | | (1.3) | (0.6) |
Derivative asset | | 0 | 0 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (13.5) | (16.4) | (14.1) |
Derivative liability | 0 | 0 | 0 |
Gas Utility | NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 1.3 | 0.6 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 13.5 | 16.4 | 14.1 |
Gas Utility | NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Utility | NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 0 | 0 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Utility | OTCBB natural gas contracts | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | 0 | 0 |
Derivative liability | 6 | 5.9 | 14.5 |
Gas Utility | OTCBB natural gas contracts | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Utility | OTCBB natural gas contracts | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 6 | 5.9 | 14.5 |
Gas Utility | OTCBB natural gas contracts | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Utility | NYMEX gasoline and heating oil contracts | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.2) | (0.3) | (1) |
Derivative liability | 0 | 0 | 0 |
Gas Utility | NYMEX gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0.2 | 0.3 | 1 |
Gas Utility | NYMEX gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Utility | NYMEX gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gas Utility | Interest rate swaps | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | | 0 |
Derivative liability | | | 2.9 |
Gas Utility | Interest rate swaps | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
Gas Utility | Interest rate swaps | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 2.9 |
Gas Utility | Interest rate swaps | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
Gas Marketing | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | | (8.4) | |
Derivative asset | | 24.7 | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | (22.3) | (21) |
Derivative liability | | 7.6 | 17.7 |
Gas Marketing | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 23.1 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 17.9 | 17 |
Gas Marketing | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 9.8 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 12 | 21.7 |
Gas Marketing | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | | 0.2 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Gas Marketing | U. S. stock/bond mutual funds | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (5.9) | | (5.4) |
Derivative asset | 31.1 | | 23.8 |
Gas Marketing | U. S. stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 18.3 | | 20.4 |
Gas Marketing | U. S. stock/bond mutual funds | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 18.5 | | 8.3 |
Gas Marketing | U. S. stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.2 | | 0.5 |
Gas Marketing | NYMEX/ICE natural gas contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (5.1) | (6.6) | (4.3) |
Derivative asset | 3.7 | 4 | 0.8 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (5.5) | (5.1) | (5.4) |
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 | 2 | 6.3 | 3.4 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 2.1 | 1.2 | 1.9 |
Gas Marketing | NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 6.8 | 4.3 | 1.7 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 3.4 | 3.9 | 3.5 |
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 | (0.8) | (0.5) | (0.5) |
Derivative asset | 7.1 | 1.2 | 2.7 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.8) | (0.5) | (0.5) |
Derivative liability | 2.9 | 1.7 | 0.3 |
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 | 7.7 | 1.5 | 2.7 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 3.7 | 2.2 | 0.8 |
Gas Marketing | Natural gas commodity contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.2 | 0.2 | 0.5 |
LIABILITIES | | | |
Derivative liability before netting adjustment | $ 0 | $ 0 | $ 0 |