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Asset Retirement Obligations
3 Months Ended
Mar. 31, 2020
Asset Retirement Obligation Disclosure [Abstract]  
Asset Retirement Obligation Disclosure [Text Block] Asset Retirement Obligations
In the first quarter of 2020, we made revisions to the estimated costs associated with refining the CCR compliance plan. The CCR rule requires the continued collection of data over time to determine the specific compliance solution. The change in estimated costs resulted in an increase to the asset retirement obligation liability of $69.8 million that was recorded in March 2020. See Note 18-C, "Environmental Matters," for additional information on CCRs.