FAIR VALUE MEASUREMENTS (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions | Mar. 31, 2017 | Sep. 30, 2016 | Mar. 31, 2016 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | $ (7) | $ (7.6) | |
Derivative liability | 6 | 4.9 | |
Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.8) | (0.7) | $ 0 |
Derivative asset | 24.7 | 25.8 | 20.2 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.5) | (1.6) | (13.7) |
Derivative liability | 0 | 0.2 | 6 |
Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 2.6 | 5.1 | |
Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 22.4 | 22.4 | 16.2 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0.5 | 1.6 | 13.7 |
Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 10.4 | 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 | 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 | 21.8 | 20.9 | 20.2 |
US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 17.7 | 16.8 | 16.2 |
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 | (1.8) | (0.4) | |
Derivative asset | 2.7 | 4.9 | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.5) | (1.6) | (13.5) |
Derivative liability | 0 | 0 | 0 |
NYMEX/ICE natural gas contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 4.5 | 5.3 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0.5 | 1.6 | 13.5 |
NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
NYMEX/ICE natural gas contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0 | 0 | 0 |
Gasoline and heating oil contracts | Laclede Gas | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | (0.3) | |
Derivative asset | 0.2 | 0 | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | | (0.2) |
Derivative liability | | | 0 |
Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.2 | 0.3 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0.2 |
Gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
OTCBB natural gas contracts | Laclede Gas | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | 0 | 0 |
Derivative liability | | 0.2 | 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 | 6 |
OTCBB natural gas contracts | Significant Unobservable Inputs (Level 3) | Laclede Gas | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Other | Interest rate swaps | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | | |
Derivative asset | 0.2 | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | 0 | 0 |
Derivative liability | | 3 | 1.8 |
Other | Interest rate swaps | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Other | Interest rate swaps | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.2 | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 3 | 1.8 |
Other | Interest rate swaps | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Gas Utility | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (1.8) | (0.7) | 0 |
Derivative asset | 24.7 | 25.9 | 20.3 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.5) | (1.6) | (13.7) |
Derivative liability | 0 | 0.2 | 6 |
Gas Utility | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 22.4 | 22.5 | 16.3 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0.5 | 1.6 | 13.7 |
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 | 0.2 | 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 | 0 |
Gas Utility | US stock/bond mutual funds | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | 0 | 0 |
Derivative asset | 21.8 | 20.9 | 20.2 |
Gas Utility | US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 17.7 | 16.8 | 16.2 |
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 | (1.8) | (0.4) | |
Derivative asset | 2.7 | 4.9 | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.5) | (1.6) | (13.5) |
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 | 4.5 | 5.3 | |
LIABILITIES | | | |
Derivative liability before netting adjustment | 0.5 | 1.6 | 13.5 |
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 | Gasoline and heating oil contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | 0 | (0.3) | 0 |
Derivative asset | 0.2 | 0.1 | 0.1 |
Gas Utility | Gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.2 | 0.4 | 0.1 |
Gas Utility | Gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
Gas Utility | Gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0 | 0 | 0 |
Gas Utility | OTCBB natural gas contracts | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | 0 | 0 |
Derivative liability | | 0.2 | 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 | 6 |
Gas Utility | OTCBB natural gas contracts | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | 0 | 0 |
Gas Utility | NYMEX gasoline and heating oil contracts | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | | (0.2) |
Derivative liability | | | 0 |
Gas Utility | NYMEX gasoline and heating oil contracts | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0.2 |
Gas Utility | NYMEX gasoline and heating oil contracts | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
Gas Utility | NYMEX gasoline and heating oil contracts | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
Gas Marketing | | | |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | | | (20) |
Derivative liability | | | 10.7 |
Gas Marketing | Quoted Prices in Active Markets (Level 1) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 15.8 |
Gas Marketing | Significant Observable Inputs (Level 2) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 14.9 |
Gas Marketing | Significant Unobservable Inputs (Level 3) | | | |
LIABILITIES | | | |
Derivative liability before netting adjustment | | | 0 |
Gas Marketing | US stock/bond mutual funds | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (6.7) | (5) | (5.9) |
Derivative asset | 31 | 34.3 | 31.1 |
Gas Marketing | US stock/bond mutual funds | Quoted Prices in Active Markets (Level 1) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 23.4 | 22.9 | 18.3 |
Gas Marketing | US stock/bond mutual funds | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 14.1 | 16.2 | 18.5 |
Gas Marketing | US stock/bond mutual funds | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.2 | 0.2 | 0.2 |
Gas Marketing | NYMEX/ICE natural gas contracts | | | |
ASSETS | | | |
Effects of Netting and Cash Margin Receivables /Payables | (4.4) | (3.4) | (5.1) |
Derivative asset | 0.2 | 0.4 | 3.7 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (6) | (5.1) | (5.5) |
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 | 0.4 | 2 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 2.1 | 3.5 | 2.1 |
Gas Marketing | NYMEX/ICE natural gas contracts | Significant Observable Inputs (Level 2) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 3.6 | 3.4 | 6.8 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 3.9 | 1.6 | 3.4 |
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 | (0.5) | (0.9) | (0.8) |
Derivative asset | 5.9 | 8 | 7.1 |
LIABILITIES | | | |
Effects of Netting and Cash Margin Receivables /Payables | (0.5) | (0.9) | (0.8) |
Derivative liability | 6 | 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 | 6.2 | 8.7 | 7.7 |
LIABILITIES | | | |
Derivative liability before netting adjustment | 6.5 | 2.6 | 3.7 |
Gas Marketing | Natural gas commodity contracts | Significant Unobservable Inputs (Level 3) | | | |
ASSETS | | | |
Derivative asset before netting adjustment | 0.2 | 0.2 | 0.2 |
LIABILITIES | | | |
Derivative liability before netting adjustment | $ 0 | $ 0 | $ 0 |