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Other Commitments And Contingencies (Narrative) (Details) $ in Millions | 12 Months Ended | 28 Months Ended |
--- | --- | --- | ---
Dec. 31, 2021 USD ($) Rate MW | Dec. 31, 2020 USD ($) | Feb. 01, 2022 USD ($)
Other Commitments And Contingencies [Line Items] |  |  |
Wind power purchase agreement capacity | MW | 500 |  |
Major Rail Operators | 3 |  |
Line of Credit Facility, Amount Outstanding | $ 0.0 | $ 0.0 |
Guarantor Obligations, Current Carrying Value | 288.9 | 40.7 |
Recorded reserves to cover environmental remediation at various sites | $ 91.1 | 92.6 |
Wind Power Purchase Agreement, Purchase Percentage | Rate | 100.00% |  |
Restructuring and Related Cost, Expected Cost | $ 42.0 |  |
Subsequent Event |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Guarantor Obligations, Current Carrying Value |  |  | $ 485.2
MGP Sites |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Number of waste disposal sites identified by program | 54 |  |
Liability for estimated remediation costs | $ 85.1 | 85.0 |
Reasonably possible remediation costs variance from reserve | $ 17.0 |  |
Columbia Of Massachusetts |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Pipeline Replacement Expenses |  | 258.0 |
Coal Transportation | Maximum |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Long Term Purchase Commitment Expiration Year | 2028 |  |
Pipeline Service Agreements [Member] | Maximum |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Long Term Purchase Commitment Expiration Year | 2038 |  |
Pipeline Service Agreements [Member] | Minimum |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Long Term Purchase Commitment Expiration Year | 2022 |  |
IT Service Agreements [Member] | Maximum |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Long Term Purchase Commitment Expiration Year | 2027 |  |
Standby Letters of Credit |  |  |
Other Commitments And Contingencies [Line Items] |  |  |
Line of Credit Facility, Amount Outstanding | $ 18.9 | $ 15.2 |

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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
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