XML 87 R72.htm IDEA: XBRL DOCUMENT v3.10.0.1
Asset Retirement Obligations (Changes In Company's Liability For Asset Retirement Obligations) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Beginning Balance $ 268.7 $ 262.6
Accretion recorded as a regulatory asset 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
CCR    
Additions 59.8  
Change in estimated cash flows $ 17.7  
[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.