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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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OPERATING REVENUES - OTHER NON-UTILITY OPERATING REVENUES (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation of Operating Revenues
Revenues	$ 2,286.5	$ 2,304.5
We Power revenues
Disaggregation of Operating Revenues
Revenue amortized from deferred revenue during the period	$ 6.4
Appliance service repairs \| Maximum
Disaggregation of Operating Revenues
Duration of contract for remaining performance obligations in contract	1 year
Revenues from contracts with customers
Disaggregation of Operating Revenues
Revenues	$ 2,290.0
Other non-utility revenues \| Revenues from contracts with customers
Disaggregation of Operating Revenues
Revenues	11.6
Other non-utility revenues \| Revenues from contracts with customers \| We Power revenues
Disaggregation of Operating Revenues
Revenues	6.4
Other non-utility revenues \| Revenues from contracts with customers \| Distributed renewable solar project revenues
Disaggregation of Operating Revenues
Revenues	1.3
Transferred over time \| Other non-utility revenues \| Revenues from contracts with customers \| Appliance service repairs
Disaggregation of Operating Revenues
Revenues	$ 3.9