Asset Retirement Obligations

12 Months Ended

Dec. 31, 2018

Asset Retirement Obligation [Abstract]

We have recognized asset retirement obligations associated with various legal obligations including costs to remove and dispose of certain construction materials located within many of our facilities, certain costs to retire pipeline, removal costs for certain underground storage tanks, removal of certain pipelines known to contain PCB contamination, closure costs for certain sites including ash ponds, solid waste management units and a landfill, as well as some other nominal asset retirement obligations. We also have a significant obligation associated with the decommissioning of our two hydro facilities located in Indiana. These hydro facilities have an indeterminate life, and as such, no asset retirement obligation has been recorded.

Changes in our liability for asset retirement obligations for the years 2018 and 2017 are presented in the table below:



(in millions)	2018				2017
Beginning Balance	$	268.7			$	262.6
Accretion recorded as a regulatory asset/liability	11.1				10.3
Additions	63.3			⁽¹⁾	2.4
Settlements	(5.9		)		(15.6		)
Change in estimated cash flows	14.8			⁽¹⁾	9.0			⁽²⁾
Ending Balance	$	352.0			$	268.7

⁽¹⁾In 2018, $59.8 million of additions and $17.7 million of the change in estimated cash flows are attributed to costs associated with refining the CCR compliance plan. See Note 18-D, "Environmental Matters," for additional information on CCRs.

⁽²⁾The change in estimated cash flows for 2017 is primarily attributed to changes in estimated costs and settlement timing for electric generating stations and the changes in estimated costs for retirement of gas mains.

Certain non-legal costs of removal that have been, and continue to be, included in depreciation rates and collected in the customer rates of the rate-regulated subsidiaries are classified as "Regulatory liabilities" on the Consolidated Balance Sheets.