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Operations and Significant Accounting Policies - Supplemental Statement of Cash Flows Information - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Supplemental Cash Flow Information [Abstract]
Cash Paid for Interest – Net of Amounts Capitalized	$ 21.2	$ 18.3
Noncash Investing and Financing Activities [Abstract]
Increase in Accounts Payable for Capital Additions to Property, Plant and Equipment	5.6	4.7
Capitalized Asset Retirement Costs	3.5	1.6
AFUDC–Equity	$ 0.5	$ 0.5

X

- Definition

Increase (Decrease) in Accounts Payable for Capital Additions to Property, Plant and Equipment

+ References

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The increase (decrease) during the reporting period in the capitalized cost of equity (based on assumed rate of return) and / or borrowed funds (based on interest rate) used to finance construction of regulated assets, which is expected to be recovered through rate adjustments. As a result of this capitalization, net income is increased. This element pertains to certain regulated industries, such as public utilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
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- Definition

The increase (decrease) during the reporting period in the carrying amount of asset retirement obligations.

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Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Topic 230
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