NiSource (NI) 10-Q 2 Nov 20 2020 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 26, 2020
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-16189
Entity Registrant Name	NiSource Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	35-2108964
Entity Address, Address Line One	801 East 86th Avenue
Entity Address, City or Town	Merrillville,
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46410
City Area Code	(877)
Local Phone Number	647-5990
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		383,212,193
Entity Central Index Key	0001111711
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	NI
Security Exchange Name	NYSE
Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	Depositary Shares, each representing a 1/1,000th ownership interest in a share of 6.50% Series B
Trading Symbol	NI PR B
Security Exchange Name	NYSE

Statements Of Consolidated Inco

Statements Of Consolidated Income (Loss) - USD ($) shares in Thousands, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating Revenues
Customer revenues	[1]	$ 861.5	$ 891	$ 3,320.1	$ 3,694.7
Other revenues		41	40.5	150.6	117
Total Operating Revenues		902.5	931.5	3,470.7	3,811.7
Operating Expenses
Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization		143.1	196.7	793.9	1,130.5
Operation and maintenance		379.9	393.9	1,177.6	995.5
Depreciation and amortization		180.6	182.2	542.4	535.2
Loss on classification as held for sale		35.6	0	400.2	0
Loss (gain) on sale of fixed assets and impairments, net		0.3	(0.2)	(0.4)	(0.1)
Other taxes		70.2	67.9	224.3	221.9
Operating Costs and Expenses		809.7	840.5	3,138	2,883
Operating Income		92.8	91	332.7	928.7
Other Income (Deductions)
Interest expense, net		(95.2)	(95.9)	(285.1)	(285.6)
Other, net		8	1.3	19.9	0.3
Gain (Loss) on Extinguishment of Debt		(243.4)	0	(243.4)	0
Total Other Deductions, Net		(330.6)	(94.6)	(508.6)	(285.3)
Income (Loss) before Income Taxes		(237.8)	(3.6)	(175.9)	643.4
Income Taxes		(64.9)	(10.2)	(73.9)	121
Net Income (Loss)		(172.9)	6.6	(102)	522.4
Preferred dividends		(13.8)	(13.8)	(41.4)	(41.4)
Net Income (Loss) Available to Common Shareholders		$ (186.7)	$ (7.2)	$ (143.4)	$ 481
Earnings (Loss) Per Share
Basic Earnings (Loss) Per Share		$ (0.49)	$ (0.02)	$ (0.37)	$ 1.29
Diluted Earnings (Loss) Per Share		$ (0.49)	$ (0.02)	$ (0.37)	$ 1.28
Basic Average Common Shares Outstanding		383,800	374,100	383,500	373,796
Diluted Average Common Shares		383,800	374,100	383,500	375,195
[1]	Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues.

Statements of Consolidated Comp

Statements of Consolidated Comprehensive Income (Loss) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Income (Loss)		$ (172.9)	$ 6.6	$ (102)	$ 522.4
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale securities	[1]	1.4	0.7	1.7	5.6
Net unrealized gain (loss) on cash flow hedges	[2]	26	(50.6)	(104.6)	(100.4)
Unrecognized pension and OPEB benefit	[3]	0.9	0.4	1.9	1.7
Total other comprehensive income (loss)	[4]	28.3	(49.5)	(101)	(93.1)
Comprehensive Income (Loss)		$ (144.6)	$ (42.9)	$ (203)	$ 429.3
[1]	Net unrealized gain on available-for-sale debt securities, net of $0.4 million and $0.1 million tax expense in the third quarter of 2020 and 2019, respectively, and $0.5 million and $1.4 million tax expense for the nine months ended 2020 and 2019, respectively.
[2]	Net unrealized gain (loss) on cash flow hedges, net of $8.6 million tax expense and $16.7 million tax benefit in the third quarter of 2020 and 2019, respectively, and $34.6 million and $33.2 million tax benefit for the nine months ended 2020 and 2019, respectively.
[3]	Unrecognized pension and OPEB benefit, net of $0.2 million and $0.1 million tax expense in the third quarter of 2020 and 2019, respectively, and $0.1 million and $0.6 million tax expense for the nine months ended 2020 and 2019, respectively.
[4]	All amounts are net of tax. Amounts in parentheses indicate debits.

Statements of Consolidated Co_2

Statements of Consolidated Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ 0.4	$ 0.1	$ 0.5	$ 1.4
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	8.6	(16.7)	(34.6)	(33.2)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	$ (0.2)	$ (0.1)	$ (0.1)	$ (0.6)

Statements of Consolidated Bala

Statements of Consolidated Balance Sheets - USD ($) $ in Millions		Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment
Utility Plant		$ 20,843.4	$ 24,502.6
Accumulated depreciation and amortization		(5,659)	(7,609.3)
Net utility plant		15,184.4	16,893.3
Other property, at cost, less accumulated depreciation		894.6	18.9
Net Property, Plant and Equipment		16,079	16,912.2
Investments and Other Assets
Unconsolidated affiliates		0.9	1.3
Available-for-sale debt securities (amortized cost of $156.1 and $150.1, allowance for credit losses of $0.7 and $0, respectively		161.8	154.2
Other investments		75.3	74.7
Total Investments and Other Assets		238	230.2
Current Assets
Cash and cash equivalents		58.6	139.3
Restricted Cash		9	9.1
Accounts receivable		560.7	876.1
Allowance for credit losses		(39.3)	(19.2)
Accounts receivable, net		521.4	856.9
Gas inventory		203.3	250.9
Materials and supplies, at average cost		127	120.2
Electric production fuel, at average cost		66.2	53.6
Exchange gas receivable		24.4	48.5
Assets held for sale		1,565.7	0
Regulatory assets		132.6	225.7
Prepayments and other		112.6	149.7
Total Current Assets		2,820.8	1,853.9
Other Assets
Regulatory assets		1,915.6	2,013.9
Goodwill		1,485.9	1,485.9
Deferred charges and other		162.2	163.7
Total Other Assets		3,563.7	3,663.5
Total Assets		22,701.5	22,659.8
Stockholders' Equity
Common stock - $0.01 par value, 600,000,000 shares authorized; 383,114,130 and 382,135,680 shares outstanding, respectively		3.8	3.8
Preferred stock - $0.01 par value, 20,000,000 shares authorized; 440,000 shares outstanding		880	880
Treasury stock		(99.9)	(99.9)
Additional paid-in capital		6,684.2	6,666.2
Retained deficit		(1,849.6)	(1,370.8)
Accumulated other comprehensive loss	[1]	(193.6)	(92.6)
Total Stockholders' Equity		5,424.9	5,986.7
Long-term debt, excluding amounts due within one year		9,208.9	7,856.2
Total Capitalization		14,633.8	13,842.9
Current Liabilities
Current portion of long-term debt		21.4	13.4
Short-term borrowings		1,388.2	1,773.2
Accounts payable		410.3	666
Dividends payable - common stock		80.5	0
Dividends payable - preferred stock		19.4	0
Customer deposits and credits		229.2	256.4
Taxes accrued		147.1	231.6
Interest accrued		95.4	99.4
Risk management liabilities		96.9	12.6
Exchange gas payable		46.3	59.7
Regulatory liabilities		156	160.2
Liabilities held for sale		451.8	0
Legal and environmental		17.2	20.1
Accrued compensation and employee benefits		141.7	156.3
Claims accrued		26.3	165.4
Other accruals		119.1	131.5
Total Current Liabilities		3,446.8	3,745.8
Other Liabilities
Risk management liabilities		169.5	134
Deferred Income Tax Liabilities, Net		1,439.5	1,485.3
Deferred investment tax credits		8.8	9.7
Accrued insurance liabilities		82.4	81.5
Accrued liability for postretirement and postemployment benefits		344.4	373.2
Regulatory liabilities		1,936.8	2,352
Asset retirement obligations		424.8	416.9
Other noncurrent liabilities		214.7	218.5
Total Other Liabilities		4,620.9	5,071.1
Commitments and Contingencies		0	0
Total Capitalization and Liabilities		$ 22,701.5	$ 22,659.8
[1]	All amounts are net of tax. Amounts in parentheses indicate debits.

Statements of Consolidated Ba_2

Statements of Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Amortized Cost	$ 156.1	$ 150.1
Allowance for Credit Loss	$ (0.7)	$ 0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	600,000,000	600,000,000
Common Stock, Shares, Outstanding	383,114,130	382,135,680
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Shares Outstanding	440,000	440,000

Statements Of Consolidated Cash

Statements Of Consolidated Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net Income (Loss)	$ (102)	$ 522.4
Gain (Loss) on Extinguishment of Debt	243.4	0
Adjustments to Reconcile Net Income (Loss) to Net Cash from Operating Activities:
Depreciation and amortization	542.4	535.2
Deferred income taxes and investment tax credits	(70.8)	120.4
Loss on classification as held for sale	400.2	0
Other adjustments	13.3	18.8
Changes in Assets and Liabilities:
Components of working capital	(148.6)	146.8
Regulatory assets/liabilities	9.9	(70)
Deferred charges and other noncurrent assets	(24.6)	(76.4)
Other noncurrent liabilities	(4.6)	34.6
Net Cash Flows from Operating Activities	858.6	1,231.8
Investing Activities
Capital expenditures	(1,292.2)	(1,310)
Cost of removal	(102.1)	(84.5)
Purchases of available-for-sale securities	(94.8)	(104)
Sales of available-for-sale securities	88.9	104.1
Other investing activities	0.3	0.6
Net Cash Flows used for Investing Activities	(1,399.9)	(1,393.8)
Financing Activities
Proceeds from Issuance of Long-term Debt	2,974	750
Repayments of long-term debt and finance lease obligations	(1,616.4)	(48.5)
Issuance of short-term debt (maturity greater than 90 days)	1,350	600
Repayment of short-term debt (maturity greater than 90 days)	(1,350)	(550)
Change in short-term borrowings, net (maturity ≤ 90 days)	(385)	(412.1)
Issuance of common stock, net of issuance costs	11.2	10.9
Equity costs, premiums and other debt related costs	(246.5)	(11.9)
Dividends paid - common stock	(241.1)	(223.8)
Dividends paid - preferred stock	(35.7)	(36.7)
Net Cash Flows from Financing Activities	460.5	77.9
Change in cash, cash equivalents and restricted cash	(80.8)	(84.1)
Cash, cash equivalents and restricted cash at beginning of period	148.4	121.1
Cash, Cash Equivalents and Restricted Cash at End of Period	$ 67.6	$ 37

Statements Of Consolidated Ca_2

Statements Of Consolidated Cash Flows (Supplemental Disclosures of Cash Flow Information) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Supplemental Cash Flow [Abstract]
Capital expenditures included in current liabilities	$ 159.6	$ 187.1
Dividends declared but not paid	99.9	94.1
Assets recorded for asset retirement obligations	$ 70.3	$ 12.8

Statements Of Consolidated Equi

Statements Of Consolidated Equity - USD ($) $ in Millions	Total	Common Stock	Preferred Stock	[1]	Treasury Stock	Additional Paid-in Capital	Retained Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2018	$ 5,750.9	$ 3.8	$ 880		$ (99.9)	$ 6,403.5	$ (1,399.3)	$ (37.2)
Comprehensive Loss:
Net Income (Loss)	522.4	0	0		0	0	522.4	0
Other comprehensive income (loss), net of tax	(93.1)	0	0		0	0	0	(93.1)
Dividends:
Common stock	(298.6)	0	0		0	0	(298.6)	0
Preferred stock	(56.1)	0	0		0	0	(56.1)	0
Stock Issuances:
Employee stock purchase plan	4.2	0	0		0	4.2	0	0
Long-term incentive plan	5.7	0	0		0	5.7	0	0
401(k) and profit sharing	13.1	0	0		0	13.1	0	0
Ending balance at Sep. 30, 2019	5,848.5	3.8	880		(99.9)	6,426.5	(1,231.6)	(130.3)
Beginning balance at Jun. 30, 2019	5,976.2	3.8	880		(99.9)	6,417.1	(1,144)	(80.8)
Comprehensive Loss:
Net Income (Loss)	6.6	0	0		0	0	6.6	0
Other comprehensive income (loss), net of tax	(49.5)	0	0		0	0	0	(49.5)
Dividends:
Common stock	(74.8)	0	0		0	0	(74.8)	0
Preferred stock	(19.4)	0	0		0	0	(19.4)	0
Stock Issuances:
Employee stock purchase plan	1.5	0	0		0	1.5	0	0
Long-term incentive plan	3.6	0	0		0	3.6	0	0
401(k) and profit sharing	4.3	0	0		0	4.3	0	0
Ending balance at Sep. 30, 2019	5,848.5	3.8	880		(99.9)	6,426.5	(1,231.6)	(130.3)
Beginning balance at Dec. 31, 2019	5,986.7	3.8	880		(99.9)	6,666.2	(1,370.8)	(92.6)
Comprehensive Loss:
Net Income (Loss)	(102)	0	0		0	0	(102)	0
Other comprehensive income (loss), net of tax	(101)	0	0		0	0	0	(101)
Dividends:
Common stock	(321.7)	0	0		0	0	(321.7)	0
Preferred stock	(55.1)	0	0		0	0	(55.1)	0
Stock Issuances:
Employee stock purchase plan	4.2	0	0		0	4.2	0	0
Long-term incentive plan	3.1	0	0		0	3.1	0	0
401(k) and profit sharing	10.7	0	0		0	10.7	0	0
Ending balance at Sep. 30, 2020	5,424.9	3.8	880		(99.9)	6,684.2	(1,849.6)	(193.6)
Beginning balance at Jun. 30, 2020	5,661.8	3.8	880		(99.9)	6,676.5	(1,576.7)	(221.9)
Comprehensive Loss:
Net Income (Loss)	(172.9)	0	0		0	0	(172.9)	0
Other comprehensive income (loss), net of tax	28.3	0	0		0	0	0	28.3
Dividends:
Common stock	(80.6)	0	0		0	0	(80.6)	0
Preferred stock	(19.4)	0	0		0	0	(19.4)	0
Stock Issuances:
Employee stock purchase plan	1.5	0	0		0	1.5	0	0
Long-term incentive plan	3.2	0	0		0	3.2	0	0
401(k) and profit sharing	3	0	0		0	3	0	0
Ending balance at Sep. 30, 2020	$ 5,424.9	$ 3.8	$ 880		$ (99.9)	$ 6,684.2	$ (1,849.6)	$ (193.6)
[1]	(1) Series A and Series B shares have an aggregate liquidation preference of $400M and $500M, respectively. See Note 5, "Equity" for additional information.

Statements of Consolidated Eq_2

Statements of Consolidated Equity (Shares) - shares shares in Thousands	Total	Preferred Stock	Common Stock	Treasury Stock
Beginning balance at Dec. 31, 2018	372,363	420	376,326	(3,963)
Issued:
Stock Issued During Period, Shares, Other	0	20	0	0
Employee stock purchase plan	153	0	153	0
Long-term incentive plan	465	0	465	0
401(k) and profit sharing	466	0	466	0
Ending balance at Sep. 30, 2019	373,447	440	377,410	(3,963)
Beginning balance at Jun. 30, 2019	373,249	440	377,212	(3,963)
Issued:
Employee stock purchase plan	51	0	51	0
Long-term incentive plan	1	0	1	0
401(k) and profit sharing	146	0	146	0
Ending balance at Sep. 30, 2019	373,447	440	377,410	(3,963)
Beginning balance at Dec. 31, 2019	382,136	440	386,099	(3,963)
Issued:
Employee stock purchase plan	171	0	171	0
Long-term incentive plan	381	0	381	0
401(k) and profit sharing	426	0	426	0
Ending balance at Sep. 30, 2020	383,114	440	387,077	(3,963)
Beginning balance at Jun. 30, 2020	382,917	440	386,880	(3,963)
Issued:
Employee stock purchase plan	65	0	65	0
Long-term incentive plan	2	0	2	0
401(k) and profit sharing	130	0	130	0
Ending balance at Sep. 30, 2020	383,114	440	387,077	(3,963)

Statements Of Consolidated Eq_3

Statements Of Consolidated Equity (Parenthetical) $ in Millions	Sep. 30, 2020USD ($)
Series A Preferred Stock
Preferred Stock, Liquidation Preference, Value	$ 400
Series B Preferred Stock
Preferred Stock, Liquidation Preference, Value	$ 500

Basis of Accounting Presentatio

Basis of Accounting Presentation	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting Presentation	Basis of Accounting Presentation Our accompanying Condensed Consolidated Financial Statements (unaudited) reflect all normal recurring adjustments that are necessary, in the opinion of management, to present fairly the results of operations in accordance with GAAP in the United States of America. The accompanying financial statements contain our accounts and that of our majority-owned or controlled subsidiaries. The accompanying financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2019. Income for interim periods may not be indicative of results for the calendar year due to weather variations and other factors. The Condensed Consolidated Financial Statements (unaudited) have been prepared pursuant to the rules and regulations of the SEC. Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations, although we believe that the disclosures made in this Quarterly Report on Form 10-Q are adequate to make the information herein not misleading. We continue to monitor how COVID-19 is affecting our workforce, customers, suppliers, operations, financial results and cash flow. The extent of the impact in the future will vary and depend on the duration and severity of the impact on the global, national and local economies. See Note 3, “Revenue Recognition,” Note 9, “Regulatory Matters,” and Note 14, “Income Taxes,” for information on COVID-19.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Issued Accounting Pronouncements We are currently evaluating the impact of certain ASUs on our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited), which are described below: Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans This pronouncement modifies the disclosure requirements for defined benefit pension or other postretirement benefit plans. The guidance removes disclosures that are no longer considered cost beneficial, clarifies the specific requirements of disclosures and adds disclosure requirements identified as relevant. The modifications affect annual period disclosures and must be applied on a retrospective basis to all periods presented. Annual periods ending after December 15, 2020. Early adoption is permitted. We have held discussions with our third-party specialist and identified the disclosure requirements that will impact our Notes to Condensed Consolidated Financial Statements (unaudited). We will adopt this ASU on its effective date. ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes This pronouncement simplifies the accounting for income taxes by eliminating certain exceptions to the general principles in ASC 740, income taxes. It also improves consistency of application for other areas of the guidance by clarifying and amending existing guidance. Annual periods beginning after December 15, 2020 Early adoption is permitted. We have evaluated the amendments of this pronouncement and determined it does not have an impact on the Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited). We continue to monitor the guidance as it relates to new activity or transactions that could impact our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited). We expect to adopt this ASU on its effective date. ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Statements This pronouncement provides temporary optional expedients and exceptions for applying GAAP principles to contract modifications and hedging relationships to ease the financial reporting burdens of the expected market transition from LIBOR and other interbank offered rates to alternative reference rates. Upon issuance on March 12, 2020, and will apply though December 31, 2022. We continue to evaluate the temporary expedients and options available under this guidance, and the effects of this pronouncement on our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited). We are currently identifying and evaluating contracts that may be impacted. As of September 30, 2020, we have not applied any expedients and options available under this ASU. Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2020-06, Debt with Conversion and Other Options (Subtopic 470-20) and Derivative and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity This pronouncement simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity's own equity. Specifically, the ASU "simplifies accounting for convertible instruments by removing major separation models required under current GAAP." In addition, the ASU "removes certain settlement conditions that are required for equity contracts to qualify for it" and "simplifies the diluted earnings per share (EPS) calculations in certain areas." Annual period beginning after December 15, 2021. Early adoption is permitted for annual period beginning after December 15, 2020. This pronouncement does not impact any securities we currently have on our balance sheet. We will continue to evaluate the effects of this pronouncement on our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited) as it pertains to any relevant future activity. We are currently evaluating the timing of our adoption of this ASU. Recently Adopted Accounting Pronouncements Standard Adoption ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments (ASC 326). ASC 326 revised the GAAP guidance on the impairment of most financial assets and certain other instruments that are not measured at fair value through net income. ASC 326 introduces the current expected credit loss (CECL) model that is based on expected losses for instruments measured at amortized cost rather than incurred losses. It also requires entities to record an allowance for available-for-sale debt securities rather than impair the carrying amount of the securities. Subsequent improvements to the estimated credit losses of available-for-sale debt securities will be recognized immediately in earnings, instead of over-time as they would under historic guidance. In 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivative and Hedging, and Topic 825, Financial Instruments. This pronouncement clarified and improved certain areas of guidance related to the recently issued standards on credit losses, hedging, and recognition and measurement. We adopted ASC 326 effective January 1, 2020, using a modified retrospective method. Adoption of this standard did not have material impact on our Condensed Consolidated Financial Statements (unaudited). No adjustments were made to the January 1, 2020 opening balances as a result of this adoption. As required under the modified retrospective method of adoption, results for the reporting periods beginning after January 1, 2020 are presented under ASC 326, while prior period amounts are not adjusted. See Note 3, "Revenue Recognition," and Note 11, "Fair Value," for our discussion of the implementing these standards. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326)

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	Revenue Recognition Revenue Disaggregation and Reconciliation. We disaggregate revenue from contracts with customers based upon reportable segment, as well as by customer class. As our revenues are primarily earned over a period of time and we do not earn a material amount of revenues at a point in time, revenues are not disaggregated as such below. The Gas Distribution Operations segment provides natural gas service and transportation for residential, commercial and industrial customers in Ohio, Pennsylvania, Virginia, Kentucky, Maryland, Indiana and Massachusetts. The sale of the Massachusetts Business was completed on October 9, 2020. Refer to Note 6, "Assets and Liabilities Held for Sale," for further details. The Electric Operations segment provides electric service in 20 counties in the northern part of Indiana. The tables below reconcile revenue disaggregation by customer class to segment revenue, as well as to revenues reflected on the Condensed Statements of Consolidated Income (Loss) (unaudited) for the three and nine months ended September 30, 2020 and September 30, 2019: Three Months Ended September 30, 2020 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 306.9 $ 164.8 $ — $ 471.7 Commercial 91.8 132.3 — 224.1 Industrial 42.8 102.7 — 145.5 Off-system 6.0 — — 6.0 Miscellaneous 6.8 7.2 0.2 14.2 Total Customer Revenues $ 454.3 $ 407.0 $ 0.2 $ 861.5 Other Revenues (2) 15.8 25.2 — 41.0 Total Operating Revenues $ 470.1 $ 432.2 $ 0.2 $ 902.5 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs. Three Months Ended September 30, 2019 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 288.3 $ 148.7 $ — $ 437.0 Commercial 90.9 136.3 — 227.2 Industrial 45.3 151.5 — 196.8 Off-system 16.9 — — 16.9 Miscellaneous 9.8 3.1 0.2 13.1 Total Customer Revenues $ 451.2 $ 439.6 $ 0.2 $ 891.0 Other Revenues (2) 12.4 28.1 — 40.5 Total Operating Revenues $ 463.6 $ 467.7 $ 0.2 $ 931.5 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs. Nine Months Ended September 30, 2020 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 1,518.1 $ 411.5 $ — $ 1,929.6 Commercial 483.9 365.4 — 849.3 Industrial 165.6 301.1 — 466.7 Off-system 32.7 — — 32.7 Miscellaneous 24.6 16.6 0.6 41.8 Total Customer Revenues $ 2,224.9 $ 1,094.6 $ 0.6 $ 3,320.1 Other Revenues (2) 79.5 71.1 — 150.6 Total Operating Revenues $ 2,304.4 $ 1,165.7 $ 0.6 $ 3,470.7 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs. Nine Months Ended September 30, 2019 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 1,638.6 $ 373.4 $ — $ 2,012.0 Commercial 543.2 370.7 — 913.9 Industrial 181.1 470.6 — 651.7 Off-system 60.4 — — 60.4 Miscellaneous 39.4 16.7 0.6 56.7 Total Customer Revenues $ 2,462.7 $ 1,231.4 $ 0.6 $ 3,694.7 Other Revenues (2) 43.5 73.5 — 117.0 Total Operating Revenues $ 2,506.2 $ 1,304.9 $ 0.6 $ 3,811.7 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs. Customer Accounts Receivable. Accounts receivable on our Condensed Consolidated Balance Sheets (unaudited) includes both billed and unbilled amounts, as well as certain amounts that are not related to customer revenues. Unbilled amounts of accounts receivable relate to a portion of a customer’s consumption of gas or electricity from the date of the last cycle billing through the last day of the month (balance sheet date). Factors taken into consideration when estimating unbilled revenue include historical usage, customer rates and weather. The opening and closing balances of customer receivables for the nine months ended September 30, 2020 are presented in the table below. We had no significant contract assets or liabilities during the period. Additionally, we have not incurred any significant costs to obtain or fulfill contracts. (in millions) Customer Accounts Receivable, Billed (less reserve) Customer Accounts Receivable, Unbilled (less reserve) Balance as of December 31, 2019 $ 466.6 $ 346.6 Balance as of September 30, 2020 291.0 178.8 Decrease $ (175.6) $ (167.8) Utility revenues are billed to customers monthly on a cycle basis. We generally expect that substantially all customer accounts receivable will be collected within the month following customer billing, as this revenue consists primarily of monthly, tariff-based billings for service and usage. We maintain common utility credit risk mitigation practices, including requiring deposits and actively pursuing collection of past due amounts. Our regulated operations also utilize certain regulatory mechanisms that facilitate recovery of bad debt costs within tariff-based rates, which provides further evidence of collectibility. In connection with COVID-19, certain state regulatory commissions instituted regulatory moratoriums that impacted our ability to pursue our standard credit risk mitigation practices. Following the issuance of these moratoriums, certain of our regulated operations have been authorized to recognize a regulatory asset for bad debt costs above levels currently in rates. While several of these moratoriums remain in place, we have reinstated our common credit mitigation practices where moratoriums have expired (see Note 9, "Regulatory Matters," for additional information on regulatory moratoriums and regulatory assets). It is probable that substantially all of the consideration to which we are entitled from customers will be collected upon satisfaction of performance obligations. Allowance for Credit Losses. We adopted ASC 326 effective January 1, 2020. See "Recently Adopted Accounting Pronouncements" in Note 2, "Recent Accounting Pronouncements," for more information about ASC 326. Each of our business segments pool their customer accounts receivables based on similar risk characteristics, such as customer type, geography, payment terms, and related macro-economic risks. Expected credit loss exposure is evaluated separately for each of our accounts receivable pools. Expected credit losses are established using a model that considers historical collections experience, current information, and reasonable and supportable forecasts. Relevant and reliable internal and external inputs used in the model include, but are not limited to, energy consumption trends, revenue projections, actual charge-offs data, recoveries data, shut-off orders executed data, and final bill data. We continuously evaluate available reasonable and supportable information relevant to assessing collectability of current and future receivables. We evaluate creditworthiness of specific customers periodically or when required by changes in facts and circumstances. When we become aware of a specific commercial or industrial customer's inability to pay, an allowance for expected credit losses is recorded for the relevant amount. We also monitor other circumstances that could affect our overall expected credit losses; these include, but are not limited to, creditworthiness of overall population in service territories, adverse conditions impacting an industry sector, and current economic conditions. At each reporting period, we record expected credit losses using an allowance for credit losses account. When deemed to be uncollectible, customer accounts are written-off. A rollforward of our allowance for credit losses for the three and nine months ended September 30, 2020 are presented in the tables below: Three Months Ended September 30, 2020 ( in millions ) Gas Distribution Operations Electric Operations Corporate and Other Total Beginning balance $ 25.4 $ 5.2 $ 0.8 $ 31.4 Current period provisions 8.2 2.3 — 10.5 Write-offs charged against allowance (4.3) (0.5) — (4.8) Recoveries of amounts previously written off 2.2 — — 2.2 Ending balance of the allowance for credit losses $ 31.5 $ 7.0 $ 0.8 $ 39.3 Nine Months Ended September 30, 2020 ( in millions ) Gas Distribution Operations Electric Operations Corporate and Other Total Beginning balance (1) 9.1 3.1 0.8 13.0 Current period provisions 30.6 6.7 — 37.3 Write-offs charged against allowance (18.1) (3.0) — (21.1) Recoveries of amounts previously written off 9.9 0.2 — 10.1 Ending balance of the allowance for credit losses 31.5 7.0 0.8 39.3 (1) Total beginning balance differs from that presented in the Condensed Statements of Consolidated Balance Sheet (unaudited) as it excludes Columbia of Massachusetts. Columbia of Massachusetts' customer receivables and related allowance for credit losses are classified as held for sale at September 30, 2020.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic EPS is computed by dividing net income (loss) available to common shareholders by the weighted-average number of shares of common stock outstanding for the period. The weighted-average shares outstanding for diluted EPS includes the incremental effects of the various long-term incentive compensation plans and forward agreements when the impact would be dilutive. The dilutive effects of forward agreements for the nine months ended September 30, 2019 relate to forward agreements settled in the fourth quarter of 2019. The computation of diluted average common shares for the three and nine months ended September 30, 2020 and the three months ended September 30, 2019 is not presented as we had a net loss on the Condensed Statements of Consolidated Income (Loss) (unaudited) during those periods, and any incremental shares would have had an anti-dilutive impact on EPS. The computation of diluted average common shares is as follows: Nine Months Ended September 30, (in thousands) 2019 Denominator Basic average common shares outstanding 373,796 Dilutive potential common shares: Shares contingently issuable under employee stock plans 919 Shares restricted under employee stock plans 141 Forward Agreements 339 Diluted Average Common Shares 375,195

Equity

Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Equity	Equity Common Stock. As of September 30, 2020, we had 600,000,000 shares of common stock authorized for issuance, of which 383,114,130 shares were outstanding. ATM Program and Forward Sale Agreements. On November 1, 2018, we entered into five separate equity distribution agreements pursuant to which we were able to sell up to an aggregate of $500.0 million of our common stock. Four of these agreements were then amended on August 1, 2019, and one was terminated. Pursuant to the four agreements, as amended, we may sell, from time to time, up to an aggregate of $434.4 million of our common stock. On August 6, 2020, under the ATM program, we executed a forward agreement, which allows us to issue a fixed number of shares at a price to be settled in the future. From August 7, 2020 to September 3, 2020, 2,809,029 shares were borrowed from third parties and sold by the dealer at a weighted average price of $23.25 per share. We may settle this agreement in shares, cash, or net shares by December 15, 2020. Had we settled all the shares under the forward agreement at September 30, 2020, we would have received approximately $64.6 million, based on a net price of $23.01 per share. On September 4, 2020, under the ATM program, we executed a separate forward agreement similar to that discussed above. From September 4, 2020 to September 16, 2020, 1,452,102 shares were borrowed from third parties and sold by the dealer at a weighted average price of $22.28 per share. We may settle this agreement in shares, cash, or net shares by December 15, 2020. Had we settled all the shares under the forward agreement at September 30, 2020, we would have received approximately $32.0 million, based on a net price of $22.05 per share. As of September 30, 2020, the ATM program (including the impacts of the forward sale agreements discussed above) had approximately $103.0 million of equity available for issuance. The program expires on December 31, 2020. Preferred Stock . As of September 30, 2020, we had 20,000,000 shares of preferred stock authorized for issuance, of which 440,000 shares of preferred stock in the aggregate for all series were outstanding. The following table displays preferred dividends declared for the period by outstanding series of shares: Three Months Ended Nine Months Ended September December 31, 2020 2019 2020 2019 2020 2019 (in millions except shares and per share amounts) Liquidation Preference Per Share Shares Dividends Declared Per Share Outstanding 5.650% Series A $ 1,000.00 400,000 28.25 28.25 56.50 56.50 $ 393.9 $ 393.9 6.500% Series B $ 25,000.00 20,000 406.25 406.25 1,625.00 1,674.65 $ 486.1 $ 486.1 In addition, 20,000 shares of Series B–1 Preferred Stock, par value $0.01 per share, were outstanding as of September 30, 2020. Holders of Series B–1 Preferred Stock are not entitled to receive dividend payments and have no conversion rights. The Series B–1 Preferred Stock is paired with the Series B Preferred Stock and may not be transferred, redeemed or repurchased except in connection with the simultaneous transfer, redemption or repurchase of the underlying Series B Preferred Stock. As of September 30, 2020, Series A Preferred Stock had $6.7 million of cumulative preferred dividends in arrears, or $16.63 per share, and Series B Preferred Stock had $1.4 million of cumulative preferred dividends in arrears, or $72.23 per share.

Assets and Liabilities Held for

Assets and Liabilities Held for Sale	9 Months Ended
	Sep. 30, 2020
Assets and Liabilities Held for Sale [Abstract]
Assets and Liabilities Held for Sale	Assets and Liabilities Held For Sale On February 26, 2020, NiSource and Columbia of Massachusetts entered into an Asset Purchase Agreement with Eversource (the "Asset Purchase Agreement"). Upon the terms and subject to the conditions set forth in the Asset Purchase Agreement, NiSource and Columbia of Massachusetts agreed to sell to Eversource, with certain additions and exceptions: (1) substantially all of the assets of Columbia of Massachusetts and (2) all of the assets held by any of Columbia of Massachusetts’ affiliates that primarily relate to the Massachusetts Business, and Eversource agreed to assume certain liabilities of Columbia of Massachusetts and its affiliates. The liabilities assumed by Eversource under the Asset Purchase Agreement did not include, among others, any liabilities arising out of the Greater Lawrence Incident or liabilities of Columbia of Massachusetts or its affiliates pursuant to civil claims for injury of persons or damage to property to the extent such injury or damage occurs prior to the closing in connection with the Massachusetts Business. On July 2, 2020, NiSource, Columbia of Massachusetts, Eversource and Eversource Gas Company of Massachusetts, a wholly-owned subsidiary of Eversource (“EGMA”), filed with the Massachusetts DPU a joint petition for the approval of the purchase and sale of the Massachusetts Business ("the Transaction") and a proposed multi-year rate plan. Additionally, the petition sought approval of a settlement agreement executed on July 2, 2020 (the “Settlement Agreement”) among, NiSource, Columbia of Massachusetts, Eversource, EGMA, the Massachusetts Attorney General’s Office ("Massachusetts AGO"), the Massachusetts Department of Energy Resources ("DOER"), and the Low-Income Weatherization and Fuel Assistance Program Network. Under the terms of the Settlement Agreement, NiSource agreed to make a payment in lieu of penalties in full settlement of all of the pending and potential claims, lawsuits, investigations or proceedings settled by and released by the Settlement Agreement in the amount of $56.0 million. This payment, which was withheld from the proceeds received from Eversource, will be used to create an Energy Relief Fund that will benefit customers of the Massachusetts Business. The Settlement Agreement was conditioned on its approval in full by the Massachusetts DPU no later than September 30, 2020; however, this deadline was extended to October 7, 2020. The Settlement Agreement was approved by the Massachusetts DPU on October 7, 2020, and the closing of the Transaction occurred on October 9, 2020. On October 9, 2020, NiSource and Columbia of Massachusetts received net proceeds from the sale of $1,112.6 million, which includes the $1,100.0 million purchase price and an estimate of Columbia of Massachusetts' net working capital, net of closing costs and the $56.0 million payment in lieu of penalties. Under the Asset Purchase Agreement, the final net working capital amount will be determined within 120 days from the closing date. In connection with the sale of the Massachusetts Business, NiSource and Eversource entered into a Transition Services Agreement (TSA). See Note 18-B, "Legal Proceedings," and Note 18-D, "Other Matters," for additional information regarding the sale and TSA, respectively. As of September 30, 2020, the Massachusetts Business continues to meet the requirements under GAAP to be classified as held for sale, and the assets and liabilities of the Massachusetts Business are measured at fair value, less costs to sell. Our estimated total pre-tax loss on classification as held for sale recorded in the the three and nine months ended September 30, 2020 is $35.6 million and $400.2 million, respectively, based on September 30, 2020 asset and liability balances, estimated net working capital and estimated transaction costs, including the $56.0 million payment in lieu of penalties described above. This estimated pre-tax loss is presented as Loss on Classification as Held for Sale on the Condensed Statements of Consolidated Income (Loss) (unaudited) and is subject to change based on actual transaction costs, net working capital, and asset and liability balances as of the close of the transaction on October 9, 2020. The Massachusetts Business had the following pretax income (loss) for the three and nine months ended September 30, 2020 and 2019: Three Months Ended Nine Months Ended (in millions) 2020 2019 2020 2019 Pretax Income (Loss) ($74.1) ($55.2) ($402.9) $183.5 The pretax income (loss) amounts exclude allocated executive compensation expense and interest expense for intercompany and external debt that was not assumed by Eversource or required to be repaid at closing. The pretax income (loss) amounts for the three and nine months ended September 30, 2020 and 2019 include costs directly related to the Greater Lawrence Incident. In addition, the pretax loss amounts for the three and nine months ended September 30, 2020 include the Loss on Classification as Held for Sale. The major classes of assets and liabilities classified as held for sale on the Condensed Consolidated Balance Sheets (unaudited) at September 30, 2020 were: (in millions) Assets Held for Sale Net Property, Plant and Equipment Total Current Assets Total Other Assets Loss on Classification as Held for Sale (1) Total Assets Held for Sale Gas Distribution Operations 1,705.0 161.5 91.8 (392.6) 1,565.7 Liabilities Held for Sale Long-term Debt, Excluding Amounts Due Within One Year Total Current Liabilities Total Other Liabilities Total Liabilities Held for Sale Gas Distribution Operations 41.6 60.1 350.1 451.8 (1) Amount differs from that presented in the Condensed Statements of Consolidated Income (Loss) (unaudited) due to cash already paid for certain transaction costs.

Property, Plant, and Equipment

Property, Plant, and Equipment	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Property, Plant and Equipment In the second quarter of 2020, we received approval from MISO to retire the R.M. Schahfer Generating Station in 2023. As a result of this approval, we have reclassified $903.8 million in net book value of certain plant and equipment for the R.M. Schahfer Generating Station from “Net utility plant” to “Other Property, at cost, less accumulated depreciation” on the Condensed Consolidated Balance Sheets (unaudited). The amount of plant and equipment reclassified to other property is based on current estimates of the plant and equipment that will not be utilized at retirement. As more information about plant and equipment that can be utilized beyond 2023 becomes available, additional amounts may be reclassified to other property.

Asset Retirement Obligations

Asset Retirement Obligations	9 Months Ended
	Sep. 30, 2020
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation Disclosure [Text Block]	Asset Retirement ObligationsDuring 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 $70.3 million that was recorded in 2020. See Note 18-C, "Environmental Matters," for additional information on CCRs.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2020
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory Matters	Regulatory Matters Cost Recovery and Trackers Comparability of our line item operating results is impacted by regulatory trackers that allow for the recovery in rates of certain costs such as those described below. Increases in the expenses that are the subject of trackers generally result in a corresponding increase in operating revenues and, therefore, have essentially no impact on total operating income results. Certain costs of our operating companies are significant, recurring in nature and generally outside the control of the operating companies. Some states allow the recovery of such costs through cost tracking mechanisms. Such tracking mechanisms allow for abbreviated regulatory proceedings in order for the operating companies to implement charges and recover appropriate costs. Tracking mechanisms allow for more timely recovery of such costs as compared with more traditional cost recovery mechanisms. Examples of such mechanisms include GCR adjustment mechanisms, tax riders, bad debt recovery mechanisms, electric energy efficiency programs, MISO non-fuel costs and revenues, resource capacity charges, federally mandated costs and environmental-related costs. A portion of the Gas Distribution revenue is related to the recovery of gas costs, the review and recovery of which occurs through standard regulatory proceedings. All states in our operating area require periodic review of actual gas procurement activity to determine prudence and to permit the recovery of prudently incurred costs related to the supply of gas for customers. Our distribution companies have historically been found prudent in the procurement of gas supplies to serve customers. A portion of the Electric Operations revenue is related to the recovery of fuel costs to generate power and the fuel costs related to purchased power. These costs are recovered through a FAC, a quarterly regulatory proceeding in Indiana. Infrastructure Replacement and Federally-Mandated Compliance Programs All of our operating utility companies have completed rate proceedings involving infrastructure replacement or enhancement, and have embarked upon initiatives to replace significant portions of their operating systems that are nearing the end of their useful lives. Each company's approach to cost recovery is unique, given the different laws, regulations and precedent that exist in each jurisdiction. The following table describes the most recent vintage of our regulatory programs to recover infrastructure replacement and other federally-mandated compliance investments currently in rates and those pending commission approval: (in millions) Company Program Incremental Revenue Incremental Capital Investment Investment Period Filed Status Rates Columbia of Ohio IRP - 2020 32.9 234.4 1/19-12/19 February 28, 2020 Approved May 2020 Columbia of Ohio CEP - 2020 18.0 185.1 1/19-12/19 February 28, 2020 Approved September 2020 NIPSCO - Gas TDSIC 11 (2) (1.7) 38.7 5/19-12/19 February 25, 2020 Approved July 2020 NIPSCO - Gas TDSIC 1 1.3 26.0 1/20-6/20 August 25, 2020 Order Expected January 2021 NIPSCO - Gas FMCA 3 (3) 0.3 43.0 4/19-9/19 November 26, 2019 Approved April 2020 NIPSCO - Gas FMCA 4 (3) 1.6 43.2 10/19-3/20 May 26, 2020 Approved October 2020 Columbia of Virginia SAVE - 2020 3.8 50.0 1/20-12/20 August 15, 2019 Approved December 6, 2019 January 2020 Columbia of Virginia SAVE - 2021 5.2 46.4 1/21-12/21 July 24, 2020 Order Expected January 2021 Columbia of Kentucky SMRP - 2020 4.2 40.4 1/20-12/20 October 15, 2019 Approved December 20, 2019 January 2020 Columbia of Kentucky SMRP - 2021 5.8 50.0 1/21-12/21 October 15, 2020 Order Expected Q1 2021 Columbia of Maryland STRIDE - 2020 1.3 15.0 1/20-12/20 January 29, 2020 Approved February 2020 Columbia of Maryland STRIDE - 2021 1.3 16.9 1/21-12/21 October 29, 2020 Order Expected January 2021 NIPSCO - Electric TDSIC - 6 28.1 131.1 12/18-6/19 August 21, 2019 Approved December 18, 2019 January 2020 NIPSCO - Electric TDSIC - 7 (1) 13.0 122.3 7/19-7/20 September 29, 2020 Order Expected February 2021 NIPSCO - Electric FMCA - 12 (3) 1.6 4.7 3/19-8/19 October 18, 2019 Approved February 2020 NIPSCO - Electric FMCA - 13 (3)(4) (1.2) — 9/19-2/20 April 15, 2020 Approved August 2020 Columbia of Pennsylvania DSIC - Q1 2020 0.9 28.2 12/19-2/20 April 27, 2020 Approved May 2020 Columbia of Pennsylvania DSIC - Q2 2020 0.8 28.6 3/20-5/20 June 19, 2020 Approved July 2020 Columbia of Pennsylvania DSIC - Q3 2020 2.6 85.0 6/20-8/20 September 18, 2020 Approved October 2020 (1) Incremental capital and revenue are net of amounts included in the step 2 rates. (2) Incremental revenue is net of amounts included in the step 2 rates and reflects a more typical 6-month filing period. (3) Incremental revenue is inclusive of tracker eligible operations and maintenance expense. (4) No eligible capital investments were made during the investment period. Rate Case Actions The following table describes current rate case actions as applicable in each of our jurisdictions net of tracker impacts: (in millions) Company Requested Incremental Revenue Approved or Settled Incremental Revenue Filed Status Rates NIPSCO - Electric (1) $ 21.4 $ (53.5) October 31, 2018 Approved January 2020 Columbia of Pennsylvania $ 100.4 in process April 24, 2020 Order Expected January 2021 Columbia of Maryland (2) $ 5.0 $ 2.0 May 15, 2020 Order Expected December 2020 (1) Rates were implemented in two steps, with implementation of step 1 rates effective on January 2, 2020 and step 2 rates effective on March 2, 2020. (2) On October 7, 2020, the Public Utility Law Judge issued a proposed order approving a settlement under which the parties to the case agreed upon the $2.0 million incremental revenue. The proposed order will become a final order on November 7, 2020, unless it is modified or reversed by the Maryland PSC. COVID-19 Regulatory Filings In response to COVID-19, we have engaged, or have received directives from, the regulatory commissions in the states in which we operate, as described below. Columbia of Ohio filed a Deferral Application and a Transition Plan with the PUCO on May 29, 2020. The Deferral Application requested approval to record a regulatory asset for COVID-19 incremental costs, foregone revenue from late payment fees, and bad debt expense from certain classes of customers. An order approving the Deferral Application was received on July 15, 2020. The Transition Plan requested the resumption of activities that were suspended in March 2020, including resumption of disconnects due to non-payment and billing of late payment fees beginning with the August 2020 billing cycle. The PUCO approved the Transition Plan on June 17, 2020. As of September 30, 2020, $1.9 million of incremental COVID-19 related costs were deferred to a regulatory asset. Recovery of the regulatory asset will be addressed in a future regulatory proceeding. NIPSCO received a COVID-19 order from the IURC on June 29, 2020. This order extended the disconnection moratorium and the suspension of collection of late payment fees, deposits and reconnection fees through August 14, 2020. The order requires utilities to offer payment arrangements of at least six months and requires NIPSCO to provide the IURC with information about NIPSCO’s communications with delinquent customers. On August 12, 2020, the IURC issued an order affirming the expiration of the disconnect moratorium after August 14, 2020, while requiring that six month payment plans be offered to all customers and extending the suspension for collection of late payment fees, deposits, and reconnection fees through October 12, 2020 for residential customers only. On October 7, 2020 the Office of Utility Consumer Counselor ("OUCC") filed a motion for the IURC to extend these temporary consumer protections for an additional 60 days. On October 27, the IURC issued a docket entry denying the OUCC's motion. The June 29, 2020 order also authorized NIPSCO to create a regulatory asset for COVID-19 related incremental bad debt expense as well as the costs to implement the requirements of the order. As of September 30, 2020, $4.8 million of incremental bad debt expense and costs to implement the requirements of the order were deferred to a regulatory asset. Recovery of the regulatory asset will be addressed in future base rate proceedings. Columbia of Pennsylvania received a secretarial letter issued by the Pennsylvania PUC on May 13, 2020 authorizing Pennsylvania utilities to create a regulatory asset for incremental bad debt expense incurred since March 13, 2020, above levels currently in rates. While Columbia of Pennsylvania is not authorized to defer any other incremental costs, it is required to track extraordinary non-recurring costs, and any offsetting benefits received, in connection with COVID-19. On October 13, 2020, the Pennsylvania PUC entered an order modifying its March 13, 2020 emergency order, which established a moratorium on utility service terminations. As modified, the moratorium still applies to residential customers with incomes at or below 300% of the federal poverty income guidelines (“protected customers”). For all other customers, the moratorium will be lifted on November 9, 2020, but utilities must comply with several notice requirements beyond those already in place in Pennsylvania in order to proceed with service terminations. For residential customers who are subject to termination under the revised moratorium, as of November 1, 2020, the standard winter service moratorium will be in effect until April 1, 2021, which will render service termination for delinquent accounts impractical during that period. The Pennsylvania PUC’s October 13, 2020 order also includes the following requirements: a utility shall offer a payment arrangement for a period of no less than 18 months to small business customers, as defined by a utility’s tariff, with past due amounts; utilities shall waive all connection, reconnection, late payment fees and deposit fees otherwise required for service for protected customers. Additionally, the October 13, 2020 order authorizes utilities to create a regulatory asset for any incremental expenses incurred above those embedded in rates resulting from the directives contained in the Order. As of September 30, 2020, $1.3 million of incremental bad debt expense was deferred to a regulatory asset. Recovery of any regulatory asset will be addressed in future base rate proceedings. On March 16, 2020, the VSCC ordered a moratorium on service disconnections for unpaid bills due to the effects of COVID-19, which was subsequently extended through October 5, 2020 to allow the Virginia General Assembly to address the issue. The order also suspended late payment fees, required utilities to offer payment plans of up to 12 months, and required utilities to provide certain information about customer accounts receivables to the VSCC. The VSCC moratorium expired on October 6, 2020; however, the directives requiring utilities to offer payment plans of up to 12 months and suspending service disconnections or charging of late payment fees to customers that are current on such payment plans remain in effect. On October 16, 2020, the Virginia General Assembly passed legislation that would extend the moratorium on service disconnections and late payment fees; action from the Governor on the legislation is pending. Columbia of Virginia continues its suspension of service disconnections and late payment fees until the result of the pending legislation is known. Columbia of Virginia received an order from the VSCC on April 29, 2020 authorizing Columbia of Virginia to create a regulatory asset for incremental bad debt expense, suspended late payment fees, reconnection costs, carrying costs and other incremental prudently incurred costs related to COVID-19. We are evaluating the impact of the order. Recovery of any regulatory asset, when recorded, will be addressed in future base rate proceedings. On August 31, 2020, with the Maryland governor's executive order prohibiting residential utility service terminations set to expire on September 1, 2020, the Maryland PSC issued an emergency order that prohibited residential service terminations until October 1, 2020. The Maryland PSC's August 31, 2020 emergency order also includes the following requirements: effective October 1, 2020, Maryland utilities may proceed with residential service terminations; utilities must give notice at least 45 days before terminating service on a residential account; structured payment plans offered to applicable residential customers must allow a minimum of 12 months to repay, or 24 months for certified low income customers; utilities are prohibited from collecting or requiring down payments or deposits as a condition of beginning a payment plan by any residential customer; and utilities are prohibited from refusing to negotiate or denying a payment plan to a residential customer due to such customer's failure to meet the terms and conditions of an alternate payment plan during the past 18 months. Columbia of Maryland received an order issued by the Maryland PSC on April 9, 2020, authorizing Maryland utilities to create a regulatory asset for incremental COVID-19 related costs, including incremental bad debt expense, incurred to ensure that customers have essential utility service during the state of emergency in Maryland. Such incremental costs must be offset by any benefit received in connection with COVID-19. As of September 30, 2020, Columbia of Maryland has deferred $0.5 million of incremental bad debt expense and COVID-19 related costs to a regulatory asset. Recovery of the regulatory asset will be addressed in future base rate proceedings. Columbia of Kentucky received an order from the Kentucky PSC on September 21, 2020 lifting the disconnection moratorium for all customers, effective October 20, 2020. The September 21, 2020 order also lifted the suspension of late payment and reconnection fees for non-residential customers as of October 20, 2020. For residential customers, the moratorium on late payment and reconnection fees is extended to December 31, 2020 and tracking of lost revenue is required. Residential customers with accumulated arrearages for service provided on or after March 16, 2020 through October 1, 2020 will be notified and placed on a default payment plan of equal installments for nine months beginning with the November 2020 billing cycle. Residential customers on a payment plan that default shall be offered another payment plan. Carrying charges may be applied to all arrearages arising during the default payment plan period at a rate no greater than the utility’s long-term debt rate. The Kentucky PSC order allows Columbia of Kentucky to create a regulatory asset for carrying charges on all arrearages arising during the default payment plan period. Recovery of the regulatory asset, when recorded, will be addressed in future base rate proceedings. Columbia of Kentucky is engaged with peer utilities and is working closely with the Kentucky PSC on the implementation of the September 21, 2020 order, including exploring flexible payment plans for customers who need financial assistance in order to mitigate the amount of uncollectible customer receivables and tracking of COVID-19 related costs.

Risk Management Activities

Risk Management Activities	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Risk Management Activities	Risk Management Activities We are exposed to certain risks relating to our ongoing business operations, namely commodity price risk and interest rate risk. We recognize that the prudent and selective use of derivatives may help to lower our cost of debt capital, manage our interest rate exposure and limit volatility in the price of natural gas. Risk management assets and liabilities on our derivatives are presented on the Condensed Consolidated Balance Sheets (unaudited) as shown below: (in millions) September 30, 2020 December 31, 2019 Risk Management Assets - Current (1) Interest rate risk programs $ — $ — Commodity price risk programs 13.7 0.6 Total $ 13.7 $ 0.6 Risk Management Assets - Noncurrent (2) Interest rate risk programs $ — $ — Commodity price risk programs 6.7 3.8 Total $ 6.7 $ 3.8 Risk Management Liabilities - Current Interest rate risk programs $ 92.1 $ — Commodity price risk programs 4.8 12.6 Total $ 96.9 $ 12.6 Risk Management Liabilities - Noncurrent Interest rate risk programs $ 123.3 $ 76.2 Commodity price risk programs 46.2 57.8 Total $ 169.5 $ 134.0 (1) Presented in "Prepayments and other" on the Condensed Consolidated Balance Sheets (unaudited). (2) Presented in "Deferred charges and other" on the Condensed Consolidated Balance Sheets (unaudited). Commodity Price Risk Management We, along with our utility customers, are exposed to variability in cash flows associated with natural gas purchases and volatility in natural gas prices. We purchase natural gas for sale and delivery to our retail, commercial and industrial customers, and for most customers the variability in the market price of gas is passed through in their rates. Some of our utility subsidiaries offer programs to certain customers whereby variability in the market price of gas is assumed by the respective utility. The objective of our commodity price risk programs is to mitigate the gas cost variability, for us or on behalf of our customers, associated with natural gas purchases or sales by economically hedging the various gas cost components using a combination of futures, options, forwards or other derivative contracts. NIPSCO received IURC approval to lock in a fixed price for its natural gas customers using long-term forward purchase instruments. The term of these instruments may range from five Interest Rate Risk Management As of September 30, 2020, we have two forward-starting interest rate swaps with an aggregate notional value totaling $500.0 million to hedge the variability in cash flows attributable to changes in the benchmark interest rate during the periods from the effective dates of the swaps to the anticipated dates of forecasted debt issuances, which are expected to take place by 2024. These interest rate swaps are designated as cash flow hedges. The gains and losses related to these swaps are recorded to AOCI and will be recognized in "Interest expense, net" concurrently with the recognition of interest expense on the associated debt, once issued. If it becomes probable that a hedged forecasted transaction will no longer occur, the accumulated gains or losses on the derivative will be recognized currently in "Other, net" in the Condensed Statements of Consolidated Income (Loss) (unaudited). There were no amounts excluded from effectiveness testing for derivatives in cash flow hedging relationships at September 30, 2020 and December 31, 2019. Our derivative instruments measured at fair value as of September 30, 2020 and December 31, 2019 do not contain any credit-risk-related contingent features.

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value	Fair Value A. Fair Value Measurements Recurring Fair Value Measurements The following tables present financial assets and liabilities measured and recorded at fair value on our Condensed Consolidated Balance Sheets (unaudited) on a recurring basis and their level within the fair value hierarchy as of September 30, 2020 and December 31, 2019: Recurring Fair Value Measurements (in millions) Quoted Prices in Significant Significant Balance as of Assets Risk management assets $ — $ 20.4 $ — $ 20.4 Available-for-sale debt securities — 161.8 — 161.8 Total $ — $ 182.2 $ — $ 182.2 Liabilities Risk management liabilities $ — $ 266.4 $ — $ 266.4 Total $ — $ 266.4 $ — $ 266.4 Recurring Fair Value Measurements (in millions) Quoted Prices in Significant Significant Balance as of Assets Risk management assets $ — $ 4.4 $ — $ 4.4 Available-for-sale debt securities — 154.2 — 154.2 Total $ — $ 158.6 $ — $ 158.6 Liabilities Risk management liabilities $ — $ 146.6 $ — $ 146.6 Total $ — $ 146.6 $ — $ 146.6 Risk Management Assets and Liabilities. Risk management assets and liabilities include interest rate swaps, exchange-traded NYMEX futures and NYMEX options and non-exchange-based forward purchase contracts. When utilized, exchange-traded derivative contracts are based on unadjusted quoted prices in active markets and are classified within Level 1. These financial assets and liabilities are secured with cash on deposit with the exchange; therefore, nonperformance risk has not been incorporated into these valuations. Certain non-exchange-traded derivatives are valued using broker or over-the-counter, on-line exchanges. In such cases, these non-exchange-traded derivatives are classified within Level 2. Non-exchange-based derivative instruments include swaps, forwards, and options. In certain instances, these instruments may utilize models to measure fair value. We use a similar model to value similar instruments. Valuation models utilize various inputs that include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, other observable inputs for the asset or liability and market-corroborated inputs, (i.e., inputs derived principally from or corroborated by observable market data by correlation or other means). Where observable inputs are available for substantially the full term of the asset or liability, the instrument is categorized within Level 2. Certain derivatives trade in less active markets with a lower availability of pricing information and models may be utilized in the valuation. When such inputs have a significant impact on the measurement of fair value, the instrument is categorized within Level 3. Credit risk is considered in the fair value calculation of derivative instruments that are not exchange-traded. Credit exposures are adjusted to reflect collateral agreements which reduce exposures. As of September 30, 2020 and December 31, 2019, there were no material transfers between fair value hierarchies. Additionally, there were no changes in the method or significant assumptions used to estimate the fair value of our financial instruments. Credit risk is considered in the fair value calculation of each of our forward-starting interest rate swaps, as described in Note 10, "Risk Management Activities." As they are based on observable data and valuations of similar instruments, the hedges are categorized within Level 2 of the fair value hierarchy. There was no exchange of premium at the initial date of the swaps, and we can settle the contracts at any time. NIPSCO has entered into long-term forward natural gas purchase instruments to lock in a fixed price for its natural gas customers. We value these contracts using a pricing model that incorporates market-based information when available, as these instruments trade less frequently and are classified within Level 2 of the fair value hierarchy. For additional information, see Note 10, “Risk Management Activities.” Available-for-Sale Debt Securities. Available-for-sale debt securities are investments pledged as collateral for trust accounts related to our wholly-owned insurance company. We value U.S. Treasury, corporate debt and mortgage-backed securities using a matrix pricing model that incorporates market-based information. These securities trade less frequently and are classified within Level 2. We adopted ASC 326 effective January 1, 2020. See "Recently Adopted Accounting Pronouncements" in Note 2, "Recent Accounting Pronouncements," for more information about ASC 326. Upon adoption of ASC 326, our available-for-sale debt securities impairments are recognized periodically using an allowance approach instead of an 'other than temporary' impairment model. At each reporting date, we utilize a quantitative and qualitative review process to assess the impairment of available-for-sale debt securities at the individual security level. For securities in a loss position, we evaluate our intent to sell or whether it is more-likely-than-not that we will be required to sell the security prior to the recovery of its amortized cost. If either criteria is met, the loss is recognized in earnings immediately, with the offsetting entry to the carrying value of the security. If both criteria are not met, we perform an analysis to determine whether the unrealized loss is related to credit factors. The analysis focuses on a variety of factors that include, but are not limited to, downgrade on ratings of the security, defaults in the current reporting period or projected defaults in the future, the security's yield spread over treasuries, and other relevant market data. If the unrealized loss is not related to credit factors, it is included in other comprehensive income. If the unrealized loss is related to credit factors, the loss is recognized as credit loss expense in earnings during the period, with an offsetting entry to the allowance for credit losses. The amount of the credit loss recorded to the allowance account is limited by the amount at which security's fair value is less than its amortized cost basis. If the credit losses in the allowance for credit losses are deemed uncollectible, the allowance on the uncollectible portion will be charged off, with an offsetting entry to the carrying value of the security. Subsequent improvements to the estimated credit losses of available-for-sale debt securities will be recognized immediately in earnings instead of over-time as they would under historic guidance. During the nine months ended September 30, 2020, we recorded $0.7 million as an allowance for credit losses on available-for-sale debt securities as a result of the analysis described above. Continuous credit monitoring and portfolio credit balancing mitigates our risk of credit losses on our available-for-sale debt securities. The amortized cost, gross unrealized gains and losses, allowance for credit losses, and fair value of available-for-sale securities at September 30, 2020 and December 31, 2019 were: September 30, 2020 (in millions) Amortized Gross Unrealized Gains Gross Unrealized Losses (1) Allowance for Credit Losses Fair Available-for-sale debt securities U.S. Treasury debt securities $ 31.5 $ 0.4 $ — $ — $ 31.9 Corporate/Other debt securities 124.6 7.0 (1.0) (0.7) 129.9 Total $ 156.1 $ 7.4 $ (1.0) $ (0.7) $ 161.8 December 31, 2019 (in millions) Amortized Gross Unrealized Gains Gross Unrealized Losses (2) Allowance for Credit Losses Fair Available-for-sale debt securities U.S. Treasury debt securities $ 31.4 $ 0.1 $ (0.1) $ — $ 31.4 Corporate/Other debt securities 118.7 4.2 (0.1) — 122.8 Total $ 150.1 $ 4.3 $ (0.2) $ — $ 154.2 (1) Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $0 and $20.4 million, respectively, at September 30, 2020. (2) Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $17.2 million and $12.2 million, respectively, at December 31, 2019. Realized gains and losses on available-for-sale securities were immaterial for the three and nine months ended September 30, 2020 and 2019. The cost of maturities sold is based upon specific identification. At September 30, 2020, approximately $7.0 million of U.S. Treasury debt securities and approximately $5.8 million of Corporate/Other debt securities have maturities of less than a year. There are no material items in the fair value reconciliation of Level 3 assets and liabilities measured at fair value on a recurring basis as of September 30, 2020 and December 31, 2019. Non-recurring Fair Value Measurements We measure the fair value of certain assets on a non-recurring basis, typically annually or when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. These assets include goodwill. As of September 30, 2020, the Massachusetts Business met the requirements under GAAP to be classified as held for sale, and the assets and liabilities of the Massachusetts Business are measured at fair value, less costs to sell. Our estimated total pre-tax loss for the three and nine months ended September 30, 2020 is $35.6 million and $400.2 million, respectively. For additional information, see Note 6, "Assets and Liabilities Held for Sale." B. Other Fair Value Disclosures for Financial Instruments. The carrying amount of cash and cash equivalents, restricted cash, customer deposits and short-term borrowings is a reasonable estimate of fair value due to their liquid or short-term nature. Our long-term borrowings are recorded at historical amounts. The following method and assumptions were used to estimate the fair value of each class of financial instruments. Long-term Debt. The fair value of outstanding long-term debt is estimated based on the quoted market prices for the same or similar securities. Certain premium costs associated with the early settlement of long-term debt are not taken into consideration in determining fair value. These fair value measurements are classified within Level 2 of the fair value hierarchy. As of September 30, 2020, there was no change in the method or significant assumptions used to estimate the fair value of long-term debt. The carrying amount and estimated fair values of these financial instruments were as follows: (in millions) Carrying Estimated Fair Carrying Estimated Fair Long-term debt (including current portion) $ 9,230.3 $ 10,723.5 $ 7,869.6 $ 8,764.4

Transfers Of Financial Assets

Transfers Of Financial Assets	9 Months Ended
	Sep. 30, 2020
Transfers and Servicing [Abstract]
Transfers Of Financial Assets	Transfers of Financial Assets Columbia of Ohio, NIPSCO and Columbia of Pennsylvania each maintain a receivables agreement whereby they transfer their customer accounts receivables to third-party financial institutions through wholly-owned and consolidated special purpose entities. The three agreements expire between May 2021 and October 2021 and may be further extended if mutually agreed to by the parties thereto. All receivables transferred to third parties are valued at face value, which approximates fair value due to their short-term nature. The amount of the undivided percentage ownership interest in the accounts receivables transferred is determined in part by required loss reserves under the agreements. Transfers of accounts receivable are accounted for as secured borrowings resulting in the recognition of short-term borrowings on the Condensed Consolidated Balance Sheets (unaudited). As of September 30, 2020, the maximum amount of debt that could be recognized related to our accounts receivable programs is $275.0 million. The following table reflects the gross receivables balance and net receivables transferred, as well as short-term borrowings related to the securitization transactions as of September 30, 2020 and December 31, 2019: (in millions) September 30, 2020 December 31, 2019 Gross receivables $ 421.7 $ 569.1 Less: Receivables not transferred 190.5 215.9 Net receivables transferred $ 231.2 $ 353.2 Short-term debt due to asset securitization $ 231.2 $ 353.2 For the nine months ended September 30, 2020 and 2019, $122.0 million and $139.1 million, respectively, was recorded as cash flows used for financing activities related to the change in short-term borrowings due to securitization transactions. Fees associated with the securitization transactions were $0.6 million and $0.6 million for the three months ended September 30, 2020 and 2019, respectively and $2.1 million and $2.0 million for the nine months ended September 30, 2020 and 2019, respectively. Columbia of Ohio, NIPSCO and Columbia of Pennsylvania remain responsible for collecting on the receivables securitized, and the receivables cannot be transferred to another party.

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The following presents our goodwill balance allocated by segment as of September 30, 2020: (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Goodwill $ 1,485.9 $ — $ — $ 1,485.9 For our annual goodwill impairment analysis performed as of May 1, 2020, we completed a quantitative "step 1" fair value measurement of our reporting units with a goodwill balance. This analysis incorporated the latest available income statement and cash flow projections, including significant, identifiable impacts of COVID-19 on the operations of each of our goodwill reporting units. We also incorporated other significant inputs to our fair value calculations, including discount rate and market multiples, to reflect current market conditions. The step 1 analysis performed indicated that the fair value of each reporting unit that is allocated goodwill significantly exceeded its carrying value. As a result, no impairment charge was recorded as of the May 1, 2020 test date. During the fourth quarter of 2019, in connection with the preparation of the year-end financial statements, we assessed the matters related to Columbia of Massachusetts (see Note 18-B, "Legal Proceedings") and determined a quantitative "step 1"

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our interim effective tax rates reflect the estimated annual effective tax rates for 2020 and 2019, adjusted for tax expense associated with certain discrete items. The effective tax rates for the three months ended September 30, 2020 and 2019 were 27.3% and 283.3%, respectively. The effective tax rates for the nine months ended September 30, 2020 and 2019 were 42.0% and 18.8%, respectively. These effective tax rates differ from the federal statutory tax rate of 21% primarily due to increased amortization of excess deferred federal income tax liabilities, as specified in the TCJA, tax credits, state income taxes and other permanent book-to-tax differences. These adjustments have a relative impact on the effective tax rate proportionally to pretax income or loss. The decrease in the three month effective tax rate of 256.0% in 2020 compared to 2019 is primarily attributable to the relative impact of permanent differences on lower pre-tax loss in 2019, offset by increased amortization of excess deferred federal income tax liabilities, as specified in the TCJA, in 2020. The increase in the nine month effective tax rate of 23.2% in 2020 compared to 2019 is primarily attributed to increased amortization of excess deferred federal income tax liabilities and lower state income taxes, offset by the non-deductible payment in lieu of penalties (see Note 6, "Assets and Liabilities Held for Sale," for additional information on the payment in lieu of penalties). There were no material changes recorded in 2020 to our uncertain tax positions recorded as of December 31, 2019. CARES Act Tax Matters. The CARES Act was enacted on March 27, 2020 in response to the COVID-19 pandemic. The CARES Act contains numerous income tax provisions, such as relaxing limitations on the deductibility of interest and the use of net operating losses arising in taxable years beginning after December 31, 2017. Under the provisions of the CARES Act, we have deferred payroll tax payments of approximately $21.7 million through September 30, 2020. We continue to monitor additional guidance to clarify provisions in the CARES Act (as well as under the TCJA) to determine if such guidance could ultimately increase or lessen their impact on our business and financial condition. There are no material income tax impacts on our consolidated financial position, results of operations, and cash flows during the three and nine months ended September 30, 2020.

Pension And Other Postretiremen

Pension And Other Postretirement Benefits	9 Months Ended
	Sep. 30, 2020
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Pension And Other Postretirement Benefits	Pension and Other Postretirement Benefits We provide defined contribution plans and noncontributory defined benefit retirement plans that cover certain of our employees. Benefits under the defined benefit retirement plans reflect the employees’ compensation, years of service and age at retirement. Additionally, we provide health care and life insurance benefits for certain retired employees. The majority of employees may become eligible for these benefits if they reach retirement age while working for us. The expected cost of such benefits is accrued during the employees’ years of service. We determined that, for certain rate-regulated subsidiaries, the future recovery of postretirement benefit costs is probable, and we record regulatory assets and liabilities for amounts that would otherwise have been recorded to expense or accumulated other comprehensive loss. Current rates of rate-regulated companies include postretirement benefit costs, including amortization of the regulatory assets and liabilities that arose prior to inclusion of these costs in rates. For most plans, cash contributions are remitted to grantor trusts. For the nine months ended September 30, 2020, we contributed $2.1 million to our pension plans and $16.7 million to our other postretirement benefit plans. The following table provides the components of the plans’ actuarially determined net periodic benefit cost for the three and nine months ended September 30, 2020 and 2019: Pension Benefits Other Postretirement Three Months Ended September 30, (in millions) 2020 2019 2020 2019 Components of Net Periodic Benefit Cost (1) Service cost $ 8.1 $ 7.3 $ 1.7 $ 1.3 Interest cost 13.1 18.1 3.8 4.8 Expected return on assets (28.3) (27.2) (3.6) (3.3) Amortization of prior service credit 0.2 — (0.4) (0.8) Recognized actuarial loss 8.6 11.3 1.2 0.5 Settlement loss 8.0 1.9 — — Total Net Periodic Benefit Cost $ 9.7 $ 11.4 $ 2.7 $ 2.5 (1) The service cost component and all non-service cost components of net periodic benefit cost are presented in "Operation and maintenance" and "Other, net", respectively, on the Condensed Statements of Consolidated Income (Loss) (unaudited). Pension Benefits Other Postretirement Nine Months Ended September 30, (in millions) 2020 2019 2020 2019 Components of Net Periodic Benefit Cost (1) Service cost $ 24.1 $ 21.9 $ 4.9 $ 3.9 Interest cost 40.1 54.5 11.6 14.4 Expected return on assets (85.1) (81.6) (10.8) (9.9) Amortization of prior service credit 0.6 — (1.4) (2.4) Recognized actuarial loss 26.0 34.1 3.8 1.5 Settlement loss 8.0 1.9 — — Total Net Periodic Benefit Cost $ 13.7 $ 30.8 $ 8.1 $ 7.5 (1) The service cost component and all non-service cost components of net periodic benefit cost are presented in "Operation and maintenance" and "Other, net", respectively, on the Condensed Statements of Consolidated Income (Loss) (unaudited). During the third quarter of 2020, three of our qualified pension plans met the requirement for settlement accounting. A settlement charge of $8.0 million was recorded during the third quarter of 2020. These pension plans were remeasured as a result of the settlements of all three plans, as well as the transfer of employees into and out of two qualified pension plans transferred to Eversource at the closing of the sale of the Massachusetts Business. The remeasurements led to a decrease to the net pension asset of $6.1 million, an increase to the pension benefit obligation, net of plan assets, of $0.2 million, a net decrease to regulatory assets of $1.4 million, and a net credit to accumulated other comprehensive loss of $0.2 million. Net periodic pension benefit cost for 2020 decreased by $1.4 million as a result of the interim remeasurement. The following table provides the key assumptions that were used to calculate the pension benefit obligation and the net periodic benefit cost for the plans that triggered settlement accounting: September 30, 2020 Weighted-average Assumption to Determine Benefit Obligation Discount rate 2.28 % Weighted-average Assumptions to Determine Net Periodic Benefit Costs for the period ended Discount rate - service cost 3.39 % Discount rate - interest cost 2.65 % Expected return on assets 5.20 %

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2020
Long-term Debt, Current and Noncurrent [Abstract]
Long-term Debt	Long-Term Debt On April 13, 2020, we completed the issuance and sale of $1.0 billion of 3.60% senior unsecured notes maturing in 2030, which resulted in approximately $987.8 million of net proceeds after deducting commissions and expenses. On August 18, 2020, we completed the issuance and sale of $1.25 billion of 0.95% senior unsecured notes maturing in 2025 and $750.0 million of 1.70% senior unsecured notes maturing in 2031, which resulted in approximately $1,980.4 million of net proceeds after deducting commissions and expenses. In August 2020, we executed tender offers for $969.3 million of outstanding notes consisting of a combination of our 4.45% notes due 2021, 2.65% notes due 2022, 3.85% notes due 2023, 3.65% notes due 2023, 6.25% notes due 2040, and 5.95% notes due 2041. In August and September 2020, we redeemed $609.3 million of outstanding notes representing the remainder of our 4.45% notes due 2021, 2.65% notes due 2022, 3.85% notes due 2023, and 3.65% notes due 2023 and all of our 5.89% notes due 2025. In conjunction with the debt retired, we recorded a $231.7 million loss on early extinguishment of long-term debt, primarily attributable to early redemption premiums.

Short-Term Borrowings

Short-Term Borrowings	9 Months Ended
	Sep. 30, 2020
Short-term Debt [Abstract]
Short-Term Borrowings	Short-Term Borrowings We generate short-term borrowings from our revolving credit facility, commercial paper program, accounts receivable transfer programs and term loan agreement. Each of these borrowing sources is described further below. We maintain a revolving credit facility to fund ongoing working capital requirements, including the provision of liquidity support for our commercial paper program, provide for issuance of letters of credit and also for general corporate purposes. Our revolving credit facility has a program limit of $1.85 billion and is comprised of a syndicate of banks led by Barclays. We had no outstanding borrowings under this facility as of September 30, 2020 and December 31, 2019. Our commercial paper program has a program limit of up to $1.5 billion with a dealer group comprised of Barclays, Citigroup, Credit Suisse and Wells Fargo. We had $307.0 million of commercial paper outstanding as of September 30, 2020 and $570.0 million of commercial paper outstanding as of December 31, 2019. Transfers of accounts receivable are accounted for as secured borrowings resulting in the recognition of short-term borrowings on the Condensed Consolidated Balance Sheets (unaudited). We had $231.2 million in transfers as of September 30, 2020 and $353.2 million in transfers as of December 31, 2019. Refer to Note 12, "Transfers of Financial Assets," for additional information. On April 1, 2020, we terminated and repaid in full our existing $850.0 million term loan agreement with a syndicate of banks led by MUFG Bank, Ltd. and entered into a new $850.0 million term loan agreement with a syndicate of banks led by KeyBank National Association. Any and all outstanding borrowings under the term loan agreement are due by March 31, 2021. Interest charged on borrowings depends on the variable rate structure we elect at the time of each borrowing. The available variable rate structures from which we may choose are defined in the term loan agreement. Under the agreement, we borrowed $850.0 million on April 1, 2020 with an interest rate of LIBOR plus 75 basis points. On October 14, 2020, we terminated and repaid in full our $850.0 million term loan agreement with proceeds from the sale of the Massachusetts Business. Short-term borrowings were as follows: (in millions) September 30, December 31, Commercial paper weighted-average interest rate of 0.23% and 2.03% at September 30, 2020 and December 31, 2019, respectively 307.0 570.0 Accounts receivable securitization facility 231.2 353.2 Term loan interest rate of 0.90% and 2.40% at September 30, 2020 and December 31, 2019, respectively 850.0 850.0 Total Short-Term Borrowings $ 1,388.2 $ 1,773.2 Other than for the term loan, revolving credit facility and certain commercial paper borrowings, cash flows related to the borrowings and repayments of the items listed above are presented net in the Condensed Statements of Consolidated Cash Flows (unaudited) as their maturities are less than 90 days.

Other Commitments And Contingen

Other Commitments And Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Other Commitments and Contingencies A. Guarantees and Indemnities. We and certain of our subsidiaries enter into various agreements providing financial or performance assurance to third parties on behalf of certain subsidiaries as a part of normal business. Such agreements include guarantees and stand-by letters of credit. These agreements are entered into primarily to support or enhance the creditworthiness otherwise attributed to a subsidiary on a stand-alone basis, thereby facilitating the extension of sufficient credit to accomplish the subsidiaries’ intended commercial purposes. As of September 30, 2020 and December 31, 2019, we had issued stand-by letters of credit of $10.2 million. We have provided guarantees related to our future performance under BTAs for our renewable generation projects. At September 30, 2020, our guarantees for the Rosewater and Indiana Crossroads BTAs totaled $195.6 million. The amount of each guaranty will decrease upon the substantial completion of the construction of the facilities. See “- D. Other Matters - NIPSCO 2018 Integrated Resource Plan,” below for more information. B. Legal Proceedings. On September 13, 2018, a series of fires and explosions occurred in Lawrence, Andover and North Andover, Massachusetts related to the delivery of natural gas by Columbia of Massachusetts (the "Greater Lawrence Incident"). The Greater Lawrence Incident resulted in one fatality and a number of injuries, damaged multiple homes and businesses, and caused the temporary evacuation of significant portions of each municipality. The Massachusetts Governor’s Office declared a state of emergency, authorizing the Massachusetts DPU to order another utility company to coordinate the restoration of utility services in Lawrence, Andover and North Andover. The incident resulted in the interruption of gas for approximately 7,500 gas meters, the majority of which served residences and approximately 700 of which served businesses, and the interruption of other utility service more broadly in the area. Columbia of Massachusetts has replaced the cast iron and bare steel gas pipeline system in the affected area and restored service to nearly all of the gas meters. See “- D. Other Matters - Greater Lawrence Pipeline Replacement” below for more information. On September 1, 2020, the Massachusetts Governor terminated the state of emergency declared following the Greater Lawrence Incident. We have been subject to inquiries and investigations by government authorities and regulatory agencies regarding the Greater Lawrence Incident, including the Massachusetts DPU and the Massachusetts Attorney General's Office, as described below. On February 26, 2020, the Company and Columbia of Massachusetts entered into agreements with the U.S. Attorney’s Office for the District of Massachusetts to resolve the U.S. Attorney’s Office’s investigation relating to the Greater Lawrence Incident, and on July 2, 2020, the Company and Columbia of Massachusetts entered into an agreement with the Massachusetts Attorney General’s Office (among other parties) to resolve the Massachusetts investigations, as described below. NTSB Investigation . As previously disclosed, the NTSB concluded its investigation into the Greater Lawrence Incident. We have requested closure of one remaining safety recommendation and are awaiting response from the NTSB. Massachusetts Investigations. Under Massachusetts law, the Massachusetts DPU is authorized to investigate potential violations of pipeline safety regulations and to assess a civil penalty of up to $218,647 for a violation of federal pipeline safety regulations. A separate violation occurs for each day of violation up to $2.2 million for a related series of violations. The Massachusetts DPU also is authorized to investigate potential violations of the Columbia of Massachusetts emergency response plan and to assess penalties of up to $250,000 per violation per day, or up to $20.0 million per related series of violations. Further, as a result of the declaration of emergency by the Governor, the Massachusetts DPU is authorized to investigate potential violations of the Massachusetts DPU's operational directives during the restoration efforts and assess penalties of up to $1.0 million per violation. The Massachusetts DPU conducted investigations of Columbia of Massachusetts pursuant to these authorities and approved a Settlement Agreement resolving its investigations on October 7, 2020 (defined and further described below). On October 25, 2019, the Massachusetts DPU issued two orders opening public investigations into Columbia of Massachusetts with respect to the Greater Lawrence Incident. The Massachusetts DPU opened the first investigation under its authority to determine compliance with federal and state pipeline safety laws and regulations, and to investigate Columbia of Massachusetts’ responsibility for and response to the Greater Lawrence Incident and its restoration efforts following the incident. The Massachusetts DPU opened the second investigation under its authority to determine whether a gas distribution company has violated established standards regarding acceptable performance for emergency preparedness and restoration of service to investigate efforts by Columbia of Massachusetts to prepare for and restore service following the Greater Lawrence Incident. These investigations were resolved by the Massachusetts DPU order dated October 7, 2020 approving the Settlement Agreement (defined and further described below). In connection with its investigation related to the Greater Lawrence Incident, on February 4, 2020, the Massachusetts Attorney General's Office issued a request for documents primarily focused on the restoration work following the incident. This investigation was resolved by the Massachusetts DPU order dated October 7, 2020 approving the Settlement Agreement (defined and further described below). On July 2, 2020, NiSource, Columbia of Massachusetts, Eversource and Eversource Gas Company of Massachusetts, a wholly-owned subsidiary of Eversource (“EGMA”), filed with the Massachusetts DPU a joint petition for the approval of the purchase and sale of the Massachusetts Business (the “Transaction”) as contemplated by the Asset Purchase Agreement and a proposed multi-year rate plan. The Asset Purchase Agreement provides for various closing conditions, including the receipt of the approval of the Massachusetts DPU and the final resolution or termination of all pending actions, claims and investigations, lawsuits or other legal or administrative proceedings against Columbia of Massachusetts and its affiliates under the jurisdiction of the Massachusetts DPU and all future actions, claims and investigations, lawsuits or other legal or administrative proceedings against NiSource, Columbia of Massachusetts and their affiliates relating to the Greater Lawrence Incident under the jurisdiction of the Massachusetts DPU, each as determined by NiSource in its reasonable discretion (the “DPU Required Resolution”). The petition included and sought approval of a settlement agreement executed on July 2, 2020 (the “Settlement Agreement”) among, NiSource, Columbia of Massachusetts, Eversource, EGMA, the Massachusetts Attorney General’s Office ("Massachusetts AGO"), the Massachusetts Department of Energy Resources ("DOER"), and the Low-Income Weatherization and Fuel Assistance Program Network (together with NiSource, Columbia of Massachusetts, Eversource, EGMA, the Massachusetts AGO and the DOER, the “Settling Parties”). The Settlement Agreement was conditioned on its approval by the Massachusetts DPU no later than September 30, 2020; however, this deadline was extended to October 7, 2020. The Settlement Agreement was approved by the Massachusetts DPU on October 7, 2020, and the closing of the Transaction occurred on October 9, 2020. Set forth below are certain of the descriptions of the provisions of the Settlement Agreement related to the DPU Required Resolution. The Settlement Agreement includes other provisions, including generally provisions related to ratemaking and activities of Eversource and EGMA to occur after the closing of the Transaction and other conditions, as further described in the Settlement Agreement. Termination of Massachusetts DPU Regulatory Matters . Under the Settlement Agreement, the Settling Parties agreed that the terms of the Settlement Agreement achieve the DPU Required Resolution under the Asset Purchase Agreement. Further, under the Settlement Agreement, Columbia of Massachusetts took responsibility for the Greater Lawrence Incident and agreed not to contest facts in the record sufficient to support the Massachusetts DPU’s investigations into pipeline safety and emergency response in the two public investigations that the Massachusetts DPU opened pursuant to the October 25, 2019 orders referenced above (DPU 19-140 and 19-141, respectively). If adjudicated, Columbia of Massachusetts could have been subject to the payment of penalties potentially up to the maximum allowed by law. The Settling Parties also agreed that, upon the closing of the Transaction, (1) all pending actions, claims, investigations, lawsuits and proceedings against NiSource, Columbia of Massachusetts and their affiliates, and all of the respective directors, officers, employees, agents and representatives of NiSource and Columbia of Massachusetts and their affiliates (such entities and individuals, collectively referred to as the “Discharged Persons”), under the Massachusetts DPU’s jurisdiction, shall be considered settled, resolved, and terminated; and (2) all future actions, claims, investigations, lawsuits and proceedings, whether known or unknown, against the Discharged Persons, in each case, relating to, arising out of, or in connection with the Greater Lawrence Incident (as defined in the Asset Purchase Agreement), under the jurisdiction of the Massachusetts DPU shall be considered settled, resolved, and terminated. This includes the Massachusetts DPU’s investigations into pipeline safety and emergency response in DPU 19-140 and 19-141, respectively, as well as any other regulatory matters that could have been raised by the Massachusetts DPU relating to, arising out of, or in connection with the Greater Lawrence Incident. The Settling Parties also agreed that, upon the closing of the Transaction, all pending actions, claims, investigations, lawsuits, and proceedings against the Discharged Persons, which are the subject of the Consent Order, shall be settled, resolved, and terminated. The “Consent Order” is a consent order the Massachusetts DPU issued on August 14, 2020 in DPU 19-140, which included Compliance Actions (as defined in the Consent Order) that corresponded to the entirety of cases pending before the Massachusetts DPU as of July 2, 2020. The Settling Parties further agreed, upon the closing of the Transaction, that the Consent Order (and the Massachusetts DPU’s associated Compliance Actions) addresses all outstanding pipeline safety compliance investigations, inquiries, or ongoing matters, regardless of whether subject to notices of probable violations (NOPVs) or related to the Greater Lawrence Incident, existing as of the execution date of the Settlement Agreement. Termination of Massachusetts AGO Matters . Under the Settlement Agreement, the Settling Parties agreed that, upon the closing of the Transaction, the Settlement Agreement shall constitute receipt from the Massachusetts AGO of an agreement, settlement, compromise, and consent: (1) to terminate with prejudice all pending actions, claims, lawsuits, investigations, or proceedings under the jurisdiction of the Massachusetts AGO against the Discharged Persons relating, arising out of, or in connection with, the Greater Lawrence Incident; and (2) not to commence on its own behalf any new action, claim, lawsuit, investigation or proceeding against any of the Discharged Persons relating, arising out of, or in connection with, the Greater Lawrence Incident. Payment in Lieu of Penalties . Under the Settlement Agreement, the Settling Parties agreed that, at the closing of the Transaction, NiSource will make a payment in lieu of penalties in full settlement of all of the pending and potential claims, lawsuits, investigations or proceedings settled by and released by the Settlement Agreement in the amount of $56.0 million. This payment was withheld from the proceeds received from Eversource at the closing of the Transaction on October 9, 2020. See Note 6, "Assets and Liabilities Held for Sale," for additional information. Energy Relief Fund . Under the Settlement Agreement, the Settling Parties agreed that the funds derived from the NiSource payment described above will be used to create an “Energy Relief Fund,” comprised of two components, designated as the “Merrimack Valley Renewal Fund” and the “Arrearage Forgiveness Fund,” in each case as further described in the Settlement Agreement. The Merrimack Valley Renewal Fund is jointly administered by the Massachusetts AGO and DOER. The Arrearage Forgiveness Fund is jointly administered by the Massachusetts AGO and Eversource. U.S. Department of Justice Investigation. On February 26, 2020, the Company and Columbia of Massachusetts entered into agreements with the U.S. Attorney’s Office to resolve the U.S. Attorney’s Office’s investigation relating to the Greater Lawrence Incident. Columbia of Massachusetts agreed to plead guilty in the United States District Court for the District of Massachusetts (the “Court”) to violating the Natural Gas Pipeline Safety Act (the “Plea Agreement”), and the Company entered into a Deferred Prosecution Agreement (the “DPA”). On March 9, 2020, Columbia of Massachusetts entered its guilty plea pursuant to the Plea Agreement, which the Court accepted. Subsequently, Columbia of Massachusetts and the U.S. Attorney’s Office modified the Plea Agreement. On June 23, 2020, the Court sentenced Columbia of Massachusetts in accordance with the terms of the modified Plea Agreement. Under the modified Plea Agreement, Columbia of Massachusetts is subject to the following terms, among others: (i) a criminal fine in the amount of $53,030,116, which has been paid; (ii) a three year probationary period that will terminate early upon a sale of Columbia of Massachusetts or a sale of its gas distribution business to a qualified third-party buyer consistent with certain requirements, but in no event before the end of the one-year mandatory period of probation; (iii) compliance with each of the NTSB recommendations stemming from the Greater Lawrence Incident; and (iv) employment of an in-house monitor until the end of the term of probation or until the sale of Columbia of Massachusetts or its gas distribution business, whichever is earlier. On October 13, 2020, the Court, upon agreement of the U.S. Attorney's Office and Columbia Gas of Massachusetts, modified the terms of probation by ending the term of the in-house monitor. Under the DPA, the U.S. Attorney’s Office agreed to defer prosecution of the Company in connection with the Greater Lawrence Incident for a three-year period (which three-year period may be extended for twelve (12) months upon the U.S. Attorney’s Office’s determination of a breach of the DPA) subject to certain obligations of the Company, including, but not limited to, the following: (i) the Company will use reasonable best efforts to sell Columbia of Massachusetts or Columbia of Massachusetts’ gas distribution business to a qualified third-party buyer consistent with certain requirements, and, upon the completion of any such sale, the Company will cease and desist any and all gas pipeline and distribution activities in the District of Massachusetts; (ii) the Company will forfeit and pay, within 30 days of the later of the sale becoming final or the date on which post-closing adjustments to the purchase price are finally determined in accordance with the agreement to sell Columbia of Massachusetts or its gas distribution business, a fine equal to the total amount of the profit or gain, if any, from any sale of Columbia of Massachusetts or its gas distribution business, with the amount of profit or gain determined as provided in the DPA; and (iii) the Company agrees as to each of the Company’s subsidiaries involved in the distribution of gas through pipeline facilities in Massachusetts, Indiana, Ohio, Pennsylvania, Maryland, Kentucky and Virginia to implement and adhere to each of the recommendations from the NTSB stemming from the Greater Lawrence Incident. Pursuant to the DPA, if the Company complies with all of its obligations under the DPA, including, but not limited to those identified above, the U.S. Attorney’s Office will not file any criminal charges against the Company related to the Greater Lawrence Incident. If Columbia of Massachusetts withdraws its plea for any reason, if the Court rejects any aspect of the Plea Agreement, or if Columbia of Massachusetts should fail to perform an obligation under the Plea Agreement prior to the sale of Columbia of Massachusetts or its gas distribution business, the U.S. Attorney's Office may, at its sole option, render the DPA null and void. The sale of the Massachusetts Business was completed on October 9, 2020. The Company is not required to forfeit or pay any funds within 30 days of the sale of the Massachusetts Business because the Company did not realize a profit or gain from the sale as provided in the DPA. U.S. Congressional Activity. On September 30, 2019, the U.S. Protecting Our Infrastructure of Pipelines and Enhancing Safety (PIPES) Act authorizing PHMSA expired. There is no effect on PHMSA's authority. Action on past re-authorization bills has extended past the expiration date and action on this re-authorization is expected to continue into 2021. Pipeline safety jurisdiction resides with the U.S. Senate Commerce Committee and is divided between two committees in the U.S. House of Representatives (Energy and Commerce, and Transportation and Infrastructure). The Senate passed its bill on August 7, 2020. The House of Representatives has yet to reconcile its legislation and act. Certain legislative proposals, if enacted into law, may increase costs for natural gas industry companies, including the Company. Private Actions. Various lawsuits, including several purported class action lawsuits, have been filed by various affected residents or businesses in Massachusetts state courts against the Company and/or Columbia of Massachusetts in connection with the Greater Lawrence Incident. A special judge has been appointed to hear all pending and future cases and the class actions have been consolidated into one class action. On January 14, 2019, the special judge granted the parties’ joint motion to stay all cases until April 30, 2019 to allow mediation, and the parties subsequently agreed to extend the stay until July 25, 2019. The class action lawsuits allege varying causes of action, including those for strict liability for ultra-hazardous activity, negligence, private nuisance, public nuisance, premises liability, trespass, breach of warranty, breach of contract, failure to warn, unjust enrichment, consumer protection act claims, negligent, reckless and intentional infliction of emotional distress and gross negligence, and seek actual compensatory damages, plus treble damages, and punitive damages. On July 26, 2019, the Company, Columbia of Massachusetts and NiSource Corporate Services Company, a subsidiary of the Company, entered into a term sheet with the class action plaintiffs under which they agreed to settle the class action claims in connection with the Greater Lawrence Incident. Columbia of Massachusetts agreed to pay $143 million into a settlement fund to compensate the settlement class and the settlement class agreed to release Columbia of Massachusetts and affiliates from all claims arising out of or related to the Greater Lawrence Incident. The following claims are not covered under the proposed settlement because they are not part of the consolidated class action: (1) physical bodily injury and wrongful death; (2) insurance subrogation, whether equitable, contractual or otherwise; and (3) claims arising out of appliances that are subject to the Massachusetts DPU orders. Emotional distress and similar claims are covered under the proposed settlement unless they are secondary to a physical bodily injury. The settlement class is defined under the term sheet as all persons and businesses in the three municipalities of Lawrence, Andover and North Andover, Massachusetts, subject to certain limited exceptions. The motion for preliminary approval and the settlement documents were filed on September 25, 2019. The preliminary approval court hearing was held on October 7, 2019 and the court issued an order granting preliminary approval of the settlement on October 11, 2019. The Court granted final approval of the settlement on March 12, 2020. With respect to claims not included in the consolidated class action, many of the asserted wrongful death and bodily injury claims have settled, and we continue to discuss potential settlements with remaining claimants. In addition, the Commonwealth of Massachusetts is seeking reimbursement from Columbia of Massachusetts for its expenses incurred in connection with the Greater Lawrence Incident. The outcomes and impacts of such private actions are uncertain at this time. Shareholder Derivative Lawsuit. On April 28, 2020, a shareholder derivative lawsuit was filed by the City of Detroit Police and Fire Retirement System in the United States District Court for the District of Delaware against certain of the Company’s current and former directors, alleging breaches of fiduciary duty with respect to the pipeline safety management systems relating to the distribution of natural gas prior to the Greater Lawrence Incident and also including claims related to the Company’s proxy statement disclosures regarding its safety systems. The remedies sought include damages for the alleged breaches of fiduciary duty, corporate governance reforms, and restitution of any unjust enrichment. The defendants have filed a motion to dismiss the lawsuit. The motion to dismiss is fully briefed. Because of the preliminary nature of this lawsuit, the Company is not able to estimate a loss or range of loss, if any, that may be incurred in connection with this matter at this time. Financial Impact. Since the Greater Lawrence Incident, we have recorded expenses of approximately $1,036 million for third-party claims and fines, penalties and settlements associated with government investigations. We estimate that total costs related to third-party claims and fines, penalties and settlements associated with government investigations resulting from the incident will range from $1,036 million to $1,050 million, depending on the number, nature, final outcome and value of third-party claims. With regard to third-party claims, these costs include, but are not limited to, personal injury and property damage claims, damage to infrastructure, business interruption claims, and mutual aid payments to other utilities assisting with the restoration effort. These costs do not include costs of certain third-party claims and fines, penalties or settlements associated with government investigations that we are not able to estimate. These costs also do not include non-claims related and government investigation-related legal expenses resulting from the incident, the capital cost of the pipeline replacement and the payment in lieu of penalties, which are set forth in " - D. Other Matters - Greater Lawrence Incident Restoration," "- Greater Lawrence Incident Pipeline Replacement," and Note 6, "Assets and Liabilities Held for Sale," respectively. The process for estimating costs associated with third-party claims relating to the Greater Lawrence Incident requires management to exercise significant judgment based on a number of assumptions and subjective factors. As more information becomes known, management’s estimates and assumptions regarding the financial impact of the Greater Lawrence Incident may change. The aggregate amount of third-party liability insurance coverage available for losses arising from the Greater Lawrence Incident is $800 million. We have collected the entire $800 million. Total expenses related to the incident have exceeded the total amount of insurance coverage available under our policies. Refer to "- D. Other Matters - Greater Lawrence Incident Restoration," below for a summary of third-party claims-related expense activity and associated insurance recoveries recorded since the Greater Lawrence Incident. We are also party to certain other claims, regulatory and legal proceedings arising in the ordinary course of business in each state in which we have operations, none of which we believe to be individually material at this time. Due to the inherent uncertainty of litigation, there can be no assurance that the outcome or resolution of any particular claim, proceeding or investigation related to the Greater Lawrence Incident or otherwise would not have a material adverse effect on our results of operations, financial position or liquidity. Certain matters in connection with the Greater Lawrence Incident have had or may have a material impact as described above. If one or more of such additional or other matters were decided against us, the effects could be material to our results of operations in the period in which we would be required to record or adjust the related liability and could also be material to our cash flows in the periods that we would be required to pay such liability. C. Environmental Matters. Our operations are subject to environmental statutes and regulations related to air quality, water quality, hazardous waste and solid waste. We believe that we are in substantial compliance with the environmental regulations currently applicable to our operations. It is management's continued intent to address environmental issues in cooperation with regulatory authorities in such a manner as to achieve mutually acceptable compliance plans. However, there can be no assurance that fines and penalties will not be incurred. Management expects a significant portion of environmental assessment and remediation costs to be recoverable through rates for certain of our companies. As of September 30, 2020 and December 31, 2019, we had recorded a liability of $93.4 million and $104.4 million, respectively, to cover environmental remediation at various sites. The current portion of this liability is included in "Legal and environmental" in the Condensed Consolidated Balance Sheets (unaudited). The noncurrent portion is included in "Other noncurrent liabilities." We recognize costs associated with environmental remediation obligations when the incurrence of such costs is probable and the amounts can be reasonably estimated. The original estimates for remediation activities may differ materially from the amount ultimately expended. The actual future expenditures depend on many factors, including currently enacted laws and regulations, the nature and extent of impact and the method of remediation. These expenditures are not currently estimable at some sites. We periodically adjust our liability as information is collected and estimates become more refined. Electric Operations' compliance estimates disclosed below are reflective of NIPSCO's Integrated Resource Plan submitted to the IURC on October 31, 2018. Refer to " - D. Other Matters - NIPSCO 2018 Integrated Resource Plan," below for additional information. Air Future legislative and regulatory programs could significantly limit allowed GHG emissions or impose a cost or tax on GHG emissions. Additionally, rules that require further GHG reductions or impose additional requirements for natural gas facilities could impose additional costs. NiSource will carefully monitor all GHG reduction proposals and regulations. ACE Rule. On July 8, 2019, the EPA published the final ACE rule, which establishes emission guidelines for states to use when developing plans to limit carbon dioxide at coal-fired electric generating units based on heat rate improvement measures. The coal-fired units at NIPSCO’s R.M. Schahfer Generating Station and Michigan City Generating Station are potentially affected sources, and compliance requirements for these units, which NIPSCO plans to retire by the end of 2023 and 2028, respectively, will be determined by future Indiana rulemaking. The ACE rule notes that states have “broad flexibility in setting standards of performance for designated facilities” and that a state may set a “business as usual” standard for sources that have a remaining useful life “so short that imposing any costs on the electric generating unit is unreasonable.” State plans are due by 2022, and the EPA will have six months to determine completeness and then one additional year to determine whether to approve the submitted plan. States have the discretion to determine the compliance period for each source. As a result, NIPSCO will continue to monitor this matter and cannot estimate its impact at this time. Waste CERCLA. Our subsidiaries are potentially responsible parties at waste disposal sites under the CERCLA (commonly known as Superfund) and similar state laws. Under CERCLA, each potentially responsible party can be held jointly, severally and strictly liable for the remediation costs as the EPA, or state, can allow the parties to pay for remedial action or perform remedial action themselves and request reimbursement from the potentially responsible parties. Our affiliates have retained CERCLA environmental liabilities, including remediation liabilities, associated with certain current and former operations. These liabilities are not material to the Condensed Consolidated Financial Statements (unaudited). MGP. A program has been instituted to identify and investigate former MGP sites where Gas Distribution Operations subsidiaries or predecessors may have liability. The program has identified 63 such sites where liability is probable as of September 30, 2020. After the sale of the Massachusetts Business, the retained number of identified sites is 54. Remedial actions at many of these sites are being overseen by state or federal environmental agencies through consent agreements or voluntary remediation agreements. We utilize a probabilistic model to estimate our future remediation costs related to MGP sites. The model was prepared with the assistance of a third party and incorporates our experience and general industry experience with remediating MGP sites. We complete an annual refresh of the model in the second quarter of each fiscal year. No material changes to the estimated future remediation costs were noted as a result of the refresh completed as of June 30, 2020. Our total estimated liability related to the facilities subject to remediation was $88.3 million and $102.2 million at September 30, 2020 and December 31, 2019, respectively. The liability represents our best estimate of the probable cost to remediate the facilities. We believe that it is reasonably possible that remediation costs could vary by as much as $20 million in addition to the costs noted above. Remediation costs are estimated based on the best available information, applicable remediation standards at the balance sheet date and experience with similar facilities. CCRs. On April 17, 2015, the EPA issued a final rule for regulation of CCRs. The rule regulates CCRs under the RCRA Subtitle D, which determines them to be nonhazardous. The rule is implemented in phases and requires increased groundwater monitoring, reporting, recordkeeping and posting of related information to the Internet. The rule also establishes requirements related to CCR management and disposal. The rule allows NIPSCO to continue its byproduct beneficial use program. To comply with the rule, NIPSCO completed capital expenditures to modify its infrastructure and manage CCRs during 2019. The CCR rule also resulted in revisions to previously recorded legal obligations associated with the retirement of certain NIPSCO facilities. The actual asset retirement costs related to the CCR rule may vary substantially from the estimates used to record the increased asset retirement obligation due to the uncertainty about the requirements that will be established by environmental authorities, compliance strategies that will be used, and the preliminary nature of available data used to estimate costs. As allowed by the rule, NIPSCO will continue to collect data over time

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2020
Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The following tables display the components of Accumulated Other Comprehensive Loss: Three Months Ended September 30, 2020 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated (1) Balance as of July 1, 2020 $ 3.6 $ (207.8) $ (17.7) $ (221.9) Other comprehensive income before reclassifications 1.2 26.0 1.0 28.2 Amounts reclassified from accumulated other comprehensive income (loss) 0.2 — (0.1) 0.1 Net current-period other comprehensive income 1.4 26.0 0.9 28.3 Balance as of September 30, 2020 $ 5.0 $ (181.8) $ (16.8) $ (193.6) (1) All amounts are net of tax. Amounts in parentheses indicate debits. Nine Months Ended September 30, 2020 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated Other Comprehensive Loss (1) Balance as of January 1, 2020 $ 3.3 $ (77.2) $ (18.7) $ (92.6) Other comprehensive income (loss) before reclassifications 2.0 (104.6) 1.4 (101.2) Amounts reclassified from accumulated other comprehensive income (loss) (0.3) — 0.5 0.2 Net current-period other comprehensive income (loss) 1.7 (104.6) 1.9 (101.0) Balance as of September 30, 2020 $ 5.0 $ (181.8) $ (16.8) $ (193.6) (1) All amounts are net of tax. Amounts in parentheses indicate debits. Three Months Ended September 30, 2019 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated (1) Balance as of July 1, 2019 $ 2.5 $ (62.8) $ (20.5) $ (80.8) Other comprehensive income (loss) before reclassifications 0.9 (50.7) 0.2 (49.6) Amounts reclassified from accumulated other comprehensive income (loss) (0.2) 0.1 0.2 0.1 Net current-period other comprehensive income (loss) 0.7 (50.6) 0.4 (49.5) Balance as of September 30, 2019 $ 3.2 $ (113.4) $ (20.1) $ (130.3) (1) All amounts are net of tax. Amounts in parentheses indicate debits. Nine Months Ended September 30, 2019 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated Other Comprehensive Loss (1 ) Balance as of January 1, 2019 $ (2.4) $ (13.0) $ (21.8) $ (37.2) Other comprehensive income (loss) before reclassifications 5.9 (100.5) 0.7 (93.9) Amounts reclassified from accumulated other comprehensive income (loss) (0.3) 0.1 1.0 0.8 Net current-period other comprehensive income (loss) 5.6 (100.4) 1.7 (93.1) Balance as of September 30, 2019 $ 3.2 $ (113.4) $ (20.1) $ (130.3) (1) All amounts are net of tax. Amounts in parentheses indicate debits.

Other, Net

Other, Net	9 Months Ended
	Sep. 30, 2020
Other, Net [Abstract]
Other, Net	Other, Net Three Months Ended Nine Months Ended (in millions) 2020 2019 2020 2019 Interest income $ 1.3 $ 2.1 $ 4.4 $ 5.4 AFUDC equity 1.8 2.9 4.9 7.1 Charitable contributions (0.3) (1.1) (0.9) (4.0) Pension and other postretirement non-service cost 0.6 (2.8) 6.4 (8.7) Sale of emission reduction credits 4.6 — 4.6 — Miscellaneous — 0.2 0.5 0.5 Total Other, net $ 8.0 $ 1.3 $ 19.9 $ 0.3

Business Segment Information

Business Segment Information	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Business Segment Information	Business Segment InformationAt September 30, 2020, our operations are divided into two primary reportable segments. The Gas Distribution Operations segment provides natural gas service and transportation for residential, commercial and industrial customers in Ohio, Pennsylvania, Virginia, Kentucky, Maryland, Indiana and Massachusetts. The sale of the Massachusetts Business was completed on October 9, 2020. Refer to Note 6, "Assets and Liabilities Held for Sale," for further details. The Electric Operations segment provides electric service in 20 counties in the northern part of Indiana. The following table provides information about our business segments. We use operating income as our primary measurement for each of the reported segments and make decisions on finance, dividends and taxes at the corporate level on a consolidated basis. Segment revenues include intersegment sales to affiliated subsidiaries, which are eliminated in consolidation. Affiliated sales are recognized on the basis of prevailing market, regulated prices or at levels provided for under contractual agreements. Operating income is derived from revenues and expenses directly associated with each segment. Three Months Ended Nine Months Ended (in millions) 2020 2019 2020 2019 Operating Revenues Gas Distribution Operations Unaffiliated $ 470.1 $ 463.6 $ 2,304.4 $ 2,506.2 Intersegment 3.0 3.3 9.0 9.9 Total 473.1 466.9 2,313.4 2,516.1 Electric Operations Unaffiliated 432.2 467.7 1,165.7 1,304.9 Intersegment 0.1 0.2 0.5 0.6 Total 432.3 467.9 1,166.2 1,305.5 Corporate and Other Unaffiliated 0.2 0.2 0.6 0.6 Intersegment 120.5 116.9 327.9 342.2 Total 120.7 117.1 328.5 342.8 Eliminations (123.6) (120.4) (337.4) (352.7) Consolidated Operating Revenues $ 902.5 $ 931.5 $ 3,470.7 $ 3,811.7 Operating Income (Loss) Gas Distribution Operations $ (42.2) $ (48.6) $ 38.0 $ 605.8 Electric Operations 130.0 140.7 295.4 321.4 Corporate and Other 5.0 (1.1) (0.7) 1.5 Consolidated Operating Income $ 92.8 $ 91.0 $ 332.7 $ 928.7

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Tables)	9 Months Ended
	Sep. 30, 2020
Accounting Standards Update and Change in Accounting Principle [Abstract]
Description of New Accounting Pronouncements Not yet Adopted	Recently Issued Accounting Pronouncements We are currently evaluating the impact of certain ASUs on our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited), which are described below: Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans This pronouncement modifies the disclosure requirements for defined benefit pension or other postretirement benefit plans. The guidance removes disclosures that are no longer considered cost beneficial, clarifies the specific requirements of disclosures and adds disclosure requirements identified as relevant. The modifications affect annual period disclosures and must be applied on a retrospective basis to all periods presented. Annual periods ending after December 15, 2020. Early adoption is permitted. We have held discussions with our third-party specialist and identified the disclosure requirements that will impact our Notes to Condensed Consolidated Financial Statements (unaudited). We will adopt this ASU on its effective date. ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes This pronouncement simplifies the accounting for income taxes by eliminating certain exceptions to the general principles in ASC 740, income taxes. It also improves consistency of application for other areas of the guidance by clarifying and amending existing guidance. Annual periods beginning after December 15, 2020 Early adoption is permitted. We have evaluated the amendments of this pronouncement and determined it does not have an impact on the Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited). We continue to monitor the guidance as it relates to new activity or transactions that could impact our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited). We expect to adopt this ASU on its effective date. ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Statements This pronouncement provides temporary optional expedients and exceptions for applying GAAP principles to contract modifications and hedging relationships to ease the financial reporting burdens of the expected market transition from LIBOR and other interbank offered rates to alternative reference rates. Upon issuance on March 12, 2020, and will apply though December 31, 2022. We continue to evaluate the temporary expedients and options available under this guidance, and the effects of this pronouncement on our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited). We are currently identifying and evaluating contracts that may be impacted. As of September 30, 2020, we have not applied any expedients and options available under this ASU. Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2020-06, Debt with Conversion and Other Options (Subtopic 470-20) and Derivative and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity This pronouncement simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts on an entity's own equity. Specifically, the ASU "simplifies accounting for convertible instruments by removing major separation models required under current GAAP." In addition, the ASU "removes certain settlement conditions that are required for equity contracts to qualify for it" and "simplifies the diluted earnings per share (EPS) calculations in certain areas." Annual period beginning after December 15, 2021. Early adoption is permitted for annual period beginning after December 15, 2020. This pronouncement does not impact any securities we currently have on our balance sheet. We will continue to evaluate the effects of this pronouncement on our Condensed Consolidated Financial Statements (unaudited) and Notes to Condensed Consolidated Financial Statements (unaudited) as it pertains to any relevant future activity. We are currently evaluating the timing of our adoption of this ASU.
Schedule of Prospective Adoption of New Accounting Pronouncements	Recently Adopted Accounting Pronouncements Standard Adoption ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments In June 2016, the FASB issued ASU 2016-13, Measurement of Credit Losses on Financial Instruments (ASC 326). ASC 326 revised the GAAP guidance on the impairment of most financial assets and certain other instruments that are not measured at fair value through net income. ASC 326 introduces the current expected credit loss (CECL) model that is based on expected losses for instruments measured at amortized cost rather than incurred losses. It also requires entities to record an allowance for available-for-sale debt securities rather than impair the carrying amount of the securities. Subsequent improvements to the estimated credit losses of available-for-sale debt securities will be recognized immediately in earnings, instead of over-time as they would under historic guidance. In 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivative and Hedging, and Topic 825, Financial Instruments. This pronouncement clarified and improved certain areas of guidance related to the recently issued standards on credit losses, hedging, and recognition and measurement. We adopted ASC 326 effective January 1, 2020, using a modified retrospective method. Adoption of this standard did not have material impact on our Condensed Consolidated Financial Statements (unaudited). No adjustments were made to the January 1, 2020 opening balances as a result of this adoption. As required under the modified retrospective method of adoption, results for the reporting periods beginning after January 1, 2020 are presented under ASC 326, while prior period amounts are not adjusted. See Note 3, "Revenue Recognition," and Note 11, "Fair Value," for our discussion of the implementing these standards. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326)

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The tables below reconcile revenue disaggregation by customer class to segment revenue, as well as to revenues reflected on the Condensed Statements of Consolidated Income (Loss) (unaudited) for the three and nine months ended September 30, 2020 and September 30, 2019: Three Months Ended September 30, 2020 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 306.9 $ 164.8 $ — $ 471.7 Commercial 91.8 132.3 — 224.1 Industrial 42.8 102.7 — 145.5 Off-system 6.0 — — 6.0 Miscellaneous 6.8 7.2 0.2 14.2 Total Customer Revenues $ 454.3 $ 407.0 $ 0.2 $ 861.5 Other Revenues (2) 15.8 25.2 — 41.0 Total Operating Revenues $ 470.1 $ 432.2 $ 0.2 $ 902.5 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs. Three Months Ended September 30, 2019 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 288.3 $ 148.7 $ — $ 437.0 Commercial 90.9 136.3 — 227.2 Industrial 45.3 151.5 — 196.8 Off-system 16.9 — — 16.9 Miscellaneous 9.8 3.1 0.2 13.1 Total Customer Revenues $ 451.2 $ 439.6 $ 0.2 $ 891.0 Other Revenues (2) 12.4 28.1 — 40.5 Total Operating Revenues $ 463.6 $ 467.7 $ 0.2 $ 931.5 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs. Nine Months Ended September 30, 2020 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 1,518.1 $ 411.5 $ — $ 1,929.6 Commercial 483.9 365.4 — 849.3 Industrial 165.6 301.1 — 466.7 Off-system 32.7 — — 32.7 Miscellaneous 24.6 16.6 0.6 41.8 Total Customer Revenues $ 2,224.9 $ 1,094.6 $ 0.6 $ 3,320.1 Other Revenues (2) 79.5 71.1 — 150.6 Total Operating Revenues $ 2,304.4 $ 1,165.7 $ 0.6 $ 3,470.7 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs. Nine Months Ended September 30, 2019 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 1,638.6 $ 373.4 $ — $ 2,012.0 Commercial 543.2 370.7 — 913.9 Industrial 181.1 470.6 — 651.7 Off-system 60.4 — — 60.4 Miscellaneous 39.4 16.7 0.6 56.7 Total Customer Revenues $ 2,462.7 $ 1,231.4 $ 0.6 $ 3,694.7 Other Revenues (2) 43.5 73.5 — 117.0 Total Operating Revenues $ 2,506.2 $ 1,304.9 $ 0.6 $ 3,811.7 (1) Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues. (2) Other revenues represent revenue earned under alternative revenue programs.
Customer Accounts Receivable	The opening and closing balances of customer receivables for the nine months ended September 30, 2020 are presented in the table below. We had no significant contract assets or liabilities during the period. Additionally, we have not incurred any significant costs to obtain or fulfill contracts. (in millions) Customer Accounts Receivable, Billed (less reserve) Customer Accounts Receivable, Unbilled (less reserve) Balance as of December 31, 2019 $ 466.6 $ 346.6 Balance as of September 30, 2020 291.0 178.8 Decrease $ (175.6) $ (167.8)
Financing Receivable, Allowance for Credit Loss	A rollforward of our allowance for credit losses for the three and nine months ended September 30, 2020 are presented in the tables below: Three Months Ended September 30, 2020 ( in millions ) Gas Distribution Operations Electric Operations Corporate and Other Total Beginning balance $ 25.4 $ 5.2 $ 0.8 $ 31.4 Current period provisions 8.2 2.3 — 10.5 Write-offs charged against allowance (4.3) (0.5) — (4.8) Recoveries of amounts previously written off 2.2 — — 2.2 Ending balance of the allowance for credit losses $ 31.5 $ 7.0 $ 0.8 $ 39.3 Nine Months Ended September 30, 2020 ( in millions ) Gas Distribution Operations Electric Operations Corporate and Other Total Beginning balance (1) 9.1 3.1 0.8 13.0 Current period provisions 30.6 6.7 — 37.3 Write-offs charged against allowance (18.1) (3.0) — (21.1) Recoveries of amounts previously written off 9.9 0.2 — 10.1 Ending balance of the allowance for credit losses 31.5 7.0 0.8 39.3 (1) Total beginning balance differs from that presented in the Condensed Statements of Consolidated Balance Sheet (unaudited) as it excludes Columbia of Massachusetts. Columbia of Massachusetts' customer receivables and related allowance for credit losses are classified as held for sale at September 30, 2020.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Computation Of Diluted Average Common Shares	The computation of diluted average common shares is as follows: Nine Months Ended September 30, (in thousands) 2019 Denominator Basic average common shares outstanding 373,796 Dilutive potential common shares: Shares contingently issuable under employee stock plans 919 Shares restricted under employee stock plans 141 Forward Agreements 339 Diluted Average Common Shares 375,195

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Schedule of Stock by Class - Preferred	The following table displays preferred dividends declared for the period by outstanding series of shares: Three Months Ended Nine Months Ended September December 31, 2020 2019 2020 2019 2020 2019 (in millions except shares and per share amounts) Liquidation Preference Per Share Shares Dividends Declared Per Share Outstanding 5.650% Series A $ 1,000.00 400,000 28.25 28.25 56.50 56.50 $ 393.9 $ 393.9 6.500% Series B $ 25,000.00 20,000 406.25 406.25 1,625.00 1,674.65 $ 486.1 $ 486.1

Assets and Liabilities Held f_2

Assets and Liabilities Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2020
Assets and Liabilities Held for Sale [Abstract]
Disposal Groups, Including Discontinued Operations [Table Text Block]	The major classes of assets and liabilities classified as held for sale on the Condensed Consolidated Balance Sheets (unaudited) at September 30, 2020 were: (in millions) Assets Held for Sale Net Property, Plant and Equipment Total Current Assets Total Other Assets Loss on Classification as Held for Sale (1) Total Assets Held for Sale Gas Distribution Operations 1,705.0 161.5 91.8 (392.6) 1,565.7 Liabilities Held for Sale Long-term Debt, Excluding Amounts Due Within One Year Total Current Liabilities Total Other Liabilities Total Liabilities Held for Sale Gas Distribution Operations 41.6 60.1 350.1 451.8 (1) Amount differs from that presented in the Condensed Statements of Consolidated Income (Loss) (unaudited) due to cash already paid for certain transaction costs.
Disposal Groups, Pretax Income (Loss)	The Massachusetts Business had the following pretax income (loss) for the three and nine months ended September 30, 2020 and 2019: Three Months Ended Nine Months Ended (in millions) 2020 2019 2020 2019 Pretax Income (Loss) ($74.1) ($55.2) ($402.9) $183.5

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2020
Regulatory Assets and Liabilities Disclosure [Abstract]
Schedule of Regulatory Programs	The following table describes the most recent vintage of our regulatory programs to recover infrastructure replacement and other federally-mandated compliance investments currently in rates and those pending commission approval: (in millions) Company Program Incremental Revenue Incremental Capital Investment Investment Period Filed Status Rates Columbia of Ohio IRP - 2020 32.9 234.4 1/19-12/19 February 28, 2020 Approved May 2020 Columbia of Ohio CEP - 2020 18.0 185.1 1/19-12/19 February 28, 2020 Approved September 2020 NIPSCO - Gas TDSIC 11 (2) (1.7) 38.7 5/19-12/19 February 25, 2020 Approved July 2020 NIPSCO - Gas TDSIC 1 1.3 26.0 1/20-6/20 August 25, 2020 Order Expected January 2021 NIPSCO - Gas FMCA 3 (3) 0.3 43.0 4/19-9/19 November 26, 2019 Approved April 2020 NIPSCO - Gas FMCA 4 (3) 1.6 43.2 10/19-3/20 May 26, 2020 Approved October 2020 Columbia of Virginia SAVE - 2020 3.8 50.0 1/20-12/20 August 15, 2019 Approved December 6, 2019 January 2020 Columbia of Virginia SAVE - 2021 5.2 46.4 1/21-12/21 July 24, 2020 Order Expected January 2021 Columbia of Kentucky SMRP - 2020 4.2 40.4 1/20-12/20 October 15, 2019 Approved December 20, 2019 January 2020 Columbia of Kentucky SMRP - 2021 5.8 50.0 1/21-12/21 October 15, 2020 Order Expected Q1 2021 Columbia of Maryland STRIDE - 2020 1.3 15.0 1/20-12/20 January 29, 2020 Approved February 2020 Columbia of Maryland STRIDE - 2021 1.3 16.9 1/21-12/21 October 29, 2020 Order Expected January 2021 NIPSCO - Electric TDSIC - 6 28.1 131.1 12/18-6/19 August 21, 2019 Approved December 18, 2019 January 2020 NIPSCO - Electric TDSIC - 7 (1) 13.0 122.3 7/19-7/20 September 29, 2020 Order Expected February 2021 NIPSCO - Electric FMCA - 12 (3) 1.6 4.7 3/19-8/19 October 18, 2019 Approved February 2020 NIPSCO - Electric FMCA - 13 (3)(4) (1.2) — 9/19-2/20 April 15, 2020 Approved August 2020 Columbia of Pennsylvania DSIC - Q1 2020 0.9 28.2 12/19-2/20 April 27, 2020 Approved May 2020 Columbia of Pennsylvania DSIC - Q2 2020 0.8 28.6 3/20-5/20 June 19, 2020 Approved July 2020 Columbia of Pennsylvania DSIC - Q3 2020 2.6 85.0 6/20-8/20 September 18, 2020 Approved October 2020 (1) Incremental capital and revenue are net of amounts included in the step 2 rates. (2) Incremental revenue is net of amounts included in the step 2 rates and reflects a more typical 6-month filing period. (3) Incremental revenue is inclusive of tracker eligible operations and maintenance expense. (4) No eligible capital investments were made during the investment period.
Rate Case Action	The following table describes current rate case actions as applicable in each of our jurisdictions net of tracker impacts: (in millions) Company Requested Incremental Revenue Approved or Settled Incremental Revenue Filed Status Rates NIPSCO - Electric (1) $ 21.4 $ (53.5) October 31, 2018 Approved January 2020 Columbia of Pennsylvania $ 100.4 in process April 24, 2020 Order Expected January 2021 Columbia of Maryland (2) $ 5.0 $ 2.0 May 15, 2020 Order Expected December 2020 (1) Rates were implemented in two steps, with implementation of step 1 rates effective on January 2, 2020 and step 2 rates effective on March 2, 2020. (2) On October 7, 2020, the Public Utility Law Judge issued a proposed order approving a settlement under which the parties to the case agreed upon the $2.0 million incremental revenue. The proposed order will become a final order on November 7, 2020, unless it is modified or reversed by the Maryland PSC.

Risk Management Activities (Tab

Risk Management Activities (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	Risk management assets and liabilities on our derivatives are presented on the Condensed Consolidated Balance Sheets (unaudited) as shown below: (in millions) September 30, 2020 December 31, 2019 Risk Management Assets - Current (1) Interest rate risk programs $ — $ — Commodity price risk programs 13.7 0.6 Total $ 13.7 $ 0.6 Risk Management Assets - Noncurrent (2) Interest rate risk programs $ — $ — Commodity price risk programs 6.7 3.8 Total $ 6.7 $ 3.8 Risk Management Liabilities - Current Interest rate risk programs $ 92.1 $ — Commodity price risk programs 4.8 12.6 Total $ 96.9 $ 12.6 Risk Management Liabilities - Noncurrent Interest rate risk programs $ 123.3 $ 76.2 Commodity price risk programs 46.2 57.8 Total $ 169.5 $ 134.0 (1) Presented in "Prepayments and other" on the Condensed Consolidated Balance Sheets (unaudited).

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following tables present financial assets and liabilities measured and recorded at fair value on our Condensed Consolidated Balance Sheets (unaudited) on a recurring basis and their level within the fair value hierarchy as of September 30, 2020 and December 31, 2019: Recurring Fair Value Measurements (in millions) Quoted Prices in Significant Significant Balance as of Assets Risk management assets $ — $ 20.4 $ — $ 20.4 Available-for-sale debt securities — 161.8 — 161.8 Total $ — $ 182.2 $ — $ 182.2 Liabilities Risk management liabilities $ — $ 266.4 $ — $ 266.4 Total $ — $ 266.4 $ — $ 266.4 Recurring Fair Value Measurements (in millions) Quoted Prices in Significant Significant Balance as of Assets Risk management assets $ — $ 4.4 $ — $ 4.4 Available-for-sale debt securities — 154.2 — 154.2 Total $ — $ 158.6 $ — $ 158.6 Liabilities Risk management liabilities $ — $ 146.6 $ — $ 146.6 Total $ — $ 146.6 $ — $ 146.6
Schedule of Available-For-Sale Securities	The amortized cost, gross unrealized gains and losses, allowance for credit losses, and fair value of available-for-sale securities at September 30, 2020 and December 31, 2019 were: September 30, 2020 (in millions) Amortized Gross Unrealized Gains Gross Unrealized Losses (1) Allowance for Credit Losses Fair Available-for-sale debt securities U.S. Treasury debt securities $ 31.5 $ 0.4 $ — $ — $ 31.9 Corporate/Other debt securities 124.6 7.0 (1.0) (0.7) 129.9 Total $ 156.1 $ 7.4 $ (1.0) $ (0.7) $ 161.8 December 31, 2019 (in millions) Amortized Gross Unrealized Gains Gross Unrealized Losses (2) Allowance for Credit Losses Fair Available-for-sale debt securities U.S. Treasury debt securities $ 31.4 $ 0.1 $ (0.1) $ — $ 31.4 Corporate/Other debt securities 118.7 4.2 (0.1) — 122.8 Total $ 150.1 $ 4.3 $ (0.2) $ — $ 154.2 (1) Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $0 and $20.4 million, respectively, at September 30, 2020. (2) Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $17.2 million and $12.2 million, respectively, at December 31, 2019.
Carrying Amount And Estimated Fair Values Of Financial Instruments	The carrying amount and estimated fair values of these financial instruments were as follows: (in millions) Carrying Estimated Fair Carrying Estimated Fair Long-term debt (including current portion) $ 9,230.3 $ 10,723.5 $ 7,869.6 $ 8,764.4

Transfers Of Financial Assets (

Transfers Of Financial Assets (Tables)	9 Months Ended
	Sep. 30, 2020
Transfers and Servicing [Abstract]
Schedule Of Gross And Net Receivables Transferred As Well As Short-Term Borrowings Related To The Securitization Transactions	The following table reflects the gross receivables balance and net receivables transferred, as well as short-term borrowings related to the securitization transactions as of September 30, 2020 and December 31, 2019: (in millions) September 30, 2020 December 31, 2019 Gross receivables $ 421.7 $ 569.1 Less: Receivables not transferred 190.5 215.9 Net receivables transferred $ 231.2 $ 353.2 Short-term debt due to asset securitization $ 231.2 $ 353.2

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following presents our goodwill balance allocated by segment as of September 30, 2020: (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Goodwill $ 1,485.9 $ — $ — $ 1,485.9

Pension And Other Postretirem_2

Pension And Other Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2020
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Components Of The Plans' Net Periodic Benefits Cost	The following table provides the components of the plans’ actuarially determined net periodic benefit cost for the three and nine months ended September 30, 2020 and 2019: Pension Benefits Other Postretirement Three Months Ended September 30, (in millions) 2020 2019 2020 2019 Components of Net Periodic Benefit Cost (1) Service cost $ 8.1 $ 7.3 $ 1.7 $ 1.3 Interest cost 13.1 18.1 3.8 4.8 Expected return on assets (28.3) (27.2) (3.6) (3.3) Amortization of prior service credit 0.2 — (0.4) (0.8) Recognized actuarial loss 8.6 11.3 1.2 0.5 Settlement loss 8.0 1.9 — — Total Net Periodic Benefit Cost $ 9.7 $ 11.4 $ 2.7 $ 2.5 (1) The service cost component and all non-service cost components of net periodic benefit cost are presented in "Operation and maintenance" and "Other, net", respectively, on the Condensed Statements of Consolidated Income (Loss) (unaudited). Pension Benefits Other Postretirement Nine Months Ended September 30, (in millions) 2020 2019 2020 2019 Components of Net Periodic Benefit Cost (1) Service cost $ 24.1 $ 21.9 $ 4.9 $ 3.9 Interest cost 40.1 54.5 11.6 14.4 Expected return on assets (85.1) (81.6) (10.8) (9.9) Amortization of prior service credit 0.6 — (1.4) (2.4) Recognized actuarial loss 26.0 34.1 3.8 1.5 Settlement loss 8.0 1.9 — — Total Net Periodic Benefit Cost $ 13.7 $ 30.8 $ 8.1 $ 7.5 (1) The service cost component and all non-service cost components of net periodic benefit cost are presented in "Operation and maintenance" and "Other, net", respectively, on the Condensed Statements of Consolidated Income (Loss) (unaudited).
Schedule of Defined Benefit Plans Disclosures	The following table provides the key assumptions that were used to calculate the pension benefit obligation and the net periodic benefit cost for the plans that triggered settlement accounting: September 30, 2020 Weighted-average Assumption to Determine Benefit Obligation Discount rate 2.28 % Weighted-average Assumptions to Determine Net Periodic Benefit Costs for the period ended Discount rate - service cost 3.39 % Discount rate - interest cost 2.65 % Expected return on assets 5.20 %

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	9 Months Ended
	Sep. 30, 2020
Short-term Debt [Abstract]
Schedule Of Short-Term Borrowings	Short-term borrowings were as follows: (in millions) September 30, December 31, Commercial paper weighted-average interest rate of 0.23% and 2.03% at September 30, 2020 and December 31, 2019, respectively 307.0 570.0 Accounts receivable securitization facility 231.2 353.2 Term loan interest rate of 0.90% and 2.40% at September 30, 2020 and December 31, 2019, respectively 850.0 850.0 Total Short-Term Borrowings $ 1,388.2 $ 1,773.2

Other Commitments And Conting_2

Other Commitments And Contingencies (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Expenses Incurred and Insurance Recoveries	The following table summarizes expenses incurred and insurance recoveries recorded since the Greater Lawrence Incident. This activity is presented within "Operation and maintenance" and "Other, net' in our Condensed Statements of Consolidated Income (Loss) (unaudited). Total Costs Incurred through Costs Incurred during the Three Months Ended Costs Incurred during the Nine Months Ended (in millions) December 31, 2019 September 30, 2020 Incident to Date Third-party claims $ 1,041 $ (3) $ (5) $ 1,036 Other incident-related costs 420 5 21 441 Total 1,461 2 16 1,477 Insurance recoveries recorded (800) — — (800) Total costs incurred $ 661 $ 2 $ 16 $ 677

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2020
Other Comprehensive Income (Loss), Tax [Abstract]
Components Of Accumulated Other Comprehensive Loss	The following tables display the components of Accumulated Other Comprehensive Loss: Three Months Ended September 30, 2020 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated (1) Balance as of July 1, 2020 $ 3.6 $ (207.8) $ (17.7) $ (221.9) Other comprehensive income before reclassifications 1.2 26.0 1.0 28.2 Amounts reclassified from accumulated other comprehensive income (loss) 0.2 — (0.1) 0.1 Net current-period other comprehensive income 1.4 26.0 0.9 28.3 Balance as of September 30, 2020 $ 5.0 $ (181.8) $ (16.8) $ (193.6) (1) All amounts are net of tax. Amounts in parentheses indicate debits. Nine Months Ended September 30, 2020 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated Other Comprehensive Loss (1) Balance as of January 1, 2020 $ 3.3 $ (77.2) $ (18.7) $ (92.6) Other comprehensive income (loss) before reclassifications 2.0 (104.6) 1.4 (101.2) Amounts reclassified from accumulated other comprehensive income (loss) (0.3) — 0.5 0.2 Net current-period other comprehensive income (loss) 1.7 (104.6) 1.9 (101.0) Balance as of September 30, 2020 $ 5.0 $ (181.8) $ (16.8) $ (193.6) (1) All amounts are net of tax. Amounts in parentheses indicate debits. Three Months Ended September 30, 2019 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated (1) Balance as of July 1, 2019 $ 2.5 $ (62.8) $ (20.5) $ (80.8) Other comprehensive income (loss) before reclassifications 0.9 (50.7) 0.2 (49.6) Amounts reclassified from accumulated other comprehensive income (loss) (0.2) 0.1 0.2 0.1 Net current-period other comprehensive income (loss) 0.7 (50.6) 0.4 (49.5) Balance as of September 30, 2019 $ 3.2 $ (113.4) $ (20.1) $ (130.3) (1) All amounts are net of tax. Amounts in parentheses indicate debits. Nine Months Ended September 30, 2019 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated Other Comprehensive Loss (1 ) Balance as of January 1, 2019 $ (2.4) $ (13.0) $ (21.8) $ (37.2) Other comprehensive income (loss) before reclassifications 5.9 (100.5) 0.7 (93.9) Amounts reclassified from accumulated other comprehensive income (loss) (0.3) 0.1 1.0 0.8 Net current-period other comprehensive income (loss) 5.6 (100.4) 1.7 (93.1) Balance as of September 30, 2019 $ 3.2 $ (113.4) $ (20.1) $ (130.3) (1) All amounts are net of tax. Amounts in parentheses indicate debits.

Other, Net (Tables)

Other, Net (Tables)	9 Months Ended
	Sep. 30, 2020
Other, Net [Abstract]
Schedule of Other Nonoperating Income (Expense)	Three Months Ended Nine Months Ended (in millions) 2020 2019 2020 2019 Interest income $ 1.3 $ 2.1 $ 4.4 $ 5.4 AFUDC equity 1.8 2.9 4.9 7.1 Charitable contributions (0.3) (1.1) (0.9) (4.0) Pension and other postretirement non-service cost 0.6 (2.8) 6.4 (8.7) Sale of emission reduction credits 4.6 — 4.6 — Miscellaneous — 0.2 0.5 0.5 Total Other, net $ 8.0 $ 1.3 $ 19.9 $ 0.3

Business Segment Information (T

Business Segment Information (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Schedule Of Operating Income Derived From Revenues And Expenses By Segment	At September 30, 2020, our operations are divided into two primary reportable segments. The Gas Distribution Operations segment provides natural gas service and transportation for residential, commercial and industrial customers in Ohio, Pennsylvania, Virginia, Kentucky, Maryland, Indiana and Massachusetts. The sale of the Massachusetts Business was completed on October 9, 2020. Refer to Note 6, "Assets and Liabilities Held for Sale," for further details. The Electric Operations segment provides electric service in 20 counties in the northern part of Indiana. The following table provides information about our business segments. We use operating income as our primary measurement for each of the reported segments and make decisions on finance, dividends and taxes at the corporate level on a consolidated basis. Segment revenues include intersegment sales to affiliated subsidiaries, which are eliminated in consolidation. Affiliated sales are recognized on the basis of prevailing market, regulated prices or at levels provided for under contractual agreements. Operating income is derived from revenues and expenses directly associated with each segment. Three Months Ended Nine Months Ended (in millions) 2020 2019 2020 2019 Operating Revenues Gas Distribution Operations Unaffiliated $ 470.1 $ 463.6 $ 2,304.4 $ 2,506.2 Intersegment 3.0 3.3 9.0 9.9 Total 473.1 466.9 2,313.4 2,516.1 Electric Operations Unaffiliated 432.2 467.7 1,165.7 1,304.9 Intersegment 0.1 0.2 0.5 0.6 Total 432.3 467.9 1,166.2 1,305.5 Corporate and Other Unaffiliated 0.2 0.2 0.6 0.6 Intersegment 120.5 116.9 327.9 342.2 Total 120.7 117.1 328.5 342.8 Eliminations (123.6) (120.4) (337.4) (352.7) Consolidated Operating Revenues $ 902.5 $ 931.5 $ 3,470.7 $ 3,811.7 Operating Income (Loss) Gas Distribution Operations $ (42.2) $ (48.6) $ 38.0 $ 605.8 Electric Operations 130.0 140.7 295.4 321.4 Corporate and Other 5.0 (1.1) (0.7) 1.5 Consolidated Operating Income $ 92.8 $ 91.0 $ 332.7 $ 928.7

Revenue Recognition (Narrative)

Revenue Recognition (Narrative) (Details)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Service Area By County	20

Revenue Recognition (Disaggrega

Revenue Recognition (Disaggregation of Revenue) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	$ 861.5	$ 891	$ 3,320.1	$ 3,694.7
Other revenues		41	40.5	150.6	117
Total Operating Revenues		902.5	931.5	3,470.7	3,811.7
Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	454.3	451.2	2,224.9	2,462.7
Other revenues		15.8	12.4	79.5	43.5
Total Operating Revenues		470.1	463.6	2,304.4	2,506.2
Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	407	439.6	1,094.6	1,231.4
Other revenues		25.2	28.1	71.1	73.5
Total Operating Revenues		432.2	467.7	1,165.7	1,304.9
Corporate and Other
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	0.2	0.2	0.6	0.6
Other revenues		0	0	0	0
Total Operating Revenues		0.2	0.2	0.6	0.6
Residential
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	471.7	437	1,929.6	2,012
Residential | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	306.9	288.3	1,518.1	1,638.6
Residential | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	164.8	148.7	411.5	373.4
Residential | Corporate and Other
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	0	0	0	0
Commercial
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	224.1	227.2	849.3	913.9
Commercial | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	91.8	90.9	483.9	543.2
Commercial | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	132.3	136.3	365.4	370.7
Commercial | Corporate and Other
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	0	0	0	0
Industrial
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	145.5	196.8	466.7	651.7
Industrial | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	42.8	45.3	165.6	181.1
Industrial | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	102.7	151.5	301.1	470.6
Industrial | Corporate and Other
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	0	0	0	0
Off-system
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	6	16.9	32.7	60.4
Off-system | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	6	16.9	32.7	60.4
Off-system | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	0	0	0	0
Off-system | Corporate and Other
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	0	0	0	0
Miscellaneous
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	14.2	13.1	41.8	56.7
Miscellaneous | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	6.8	9.8	24.6	39.4
Miscellaneous | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	7.2	3.1	16.6	16.7
Miscellaneous | Corporate and Other
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	$ 0.2	$ 0.2	$ 0.6	$ 0.6
[1]	Customer revenue amounts exclude intersegment revenues. See Note 21, "Business Segment Information," for discussion of intersegment revenues.

Revenue Recognition (Customer A

Revenue Recognition (Customer Accounts Receivable) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Customer Accounts Receivable, Billed (Less Reserve)	$ 291	$ 466.6
Customer Accounts Receivable, Unbilled (Less Reserve)	178.8	$ 346.6
Increase (Decrease) in Customer Accounts Receivable, Billed (Less Reserve)	(175.6)
Increase (Decrease) in Customer Accounts Receivable, Unbilled (Less Reserve)	$ (167.8)

Revenue Recognition Revenue Rec

Revenue Recognition Revenue Recognition (Allowance for Credit Losses) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Credit Loss	$ 39.3	$ 39.3	$ 31.4	$ 13
Current period provisions	10.5	37.3
Write-offs charged against allowance	(4.8)	(21.1)
Recoveries of amounts previously written off	2.2	10.1
Gas Distribution Operations
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Credit Loss	31.5	31.5	25.4	9.1
Current period provisions	8.2	30.6
Write-offs charged against allowance	(4.3)	(18.1)
Recoveries of amounts previously written off	2.2	9.9
Electric Operations
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Credit Loss	7	7	5.2	3.1
Current period provisions	2.3	6.7
Write-offs charged against allowance	(0.5)	(3)
Recoveries of amounts previously written off	0	0.2
Corporate and Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Credit Loss	0.8	0.8	$ 0.8	$ 0.8
Current period provisions	0	0
Write-offs charged against allowance	0	0
Recoveries of amounts previously written off	$ 0	$ 0

Earnings Per Share (Details)

Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Denominator
Basic Average Common Shares Outstanding	383,800	374,100	383,500	373,796
Dilutive potential common shares
Shares contingently issuable under employee stock plans				919
Shares restricted under stock plans				141
Forward agreements				339
Diluted Average Common Shares	383,800	374,100	383,500	375,195

Equity (Narrative) (Details)

Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Common Stock, Shares Authorized	600,000,000	600,000,000	600,000,000
Common Stock, Shares, Outstanding	383,114,130	383,114,130	382,135,680
Preferred Stock, Shares Authorized	20,000,000	20,000,000	20,000,000
Preferred Stock, Shares Outstanding	440,000	440,000	440,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01	$ 0.01
At The Market Program
ATM Program Equity Remaining Available for Issuance		$ 103
Forward Agreement
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share		$ 500
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value	$ 434.4	$ 434.4
Forward Agreement August 20
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share	$ 23.25	$ 23.01
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value	$ 64.6	$ 64.6
Forward Contract Indexed to Issuer's Equity, Shares	2,809,029
Forward Agreement September 20
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share	$ 22.28	$ 22.05
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value	$ 32	$ 32
Forward Contract Indexed to Issuer's Equity, Shares	1,452,102
Series A Preferred Stock
Preferred Stock, Per Share Amounts of Preferred Dividends in Arrears	$ 16.63
Preferred Stock, Amount of Preferred Dividends in Arrears	$ 6.7
Preferred Stock, Shares Outstanding	400,000	400,000
Series B Preferred Stock
Preferred Stock, Per Share Amounts of Preferred Dividends in Arrears	$ 72.23
Preferred Stock, Amount of Preferred Dividends in Arrears	$ 1.4
Preferred Stock, Shares Outstanding	20,000	20,000
Series B-1 Preferred Stock
Preferred Stock, Shares Outstanding	20,000	20,000

Equity Schedule of Stock by Cla

Equity Schedule of Stock by Class - Preferred (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding		440,000		440,000			440,000
Shares outstanding		$ 5,424.9	$ 5,848.5	$ 5,424.9	$ 5,848.5	$ 5,661.8	$ 5,986.7	$ 5,976.2	$ 5,750.9
Series A Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share		$ 1,000		$ 1,000
Preferred Stock, Shares Outstanding		400,000		400,000
Dividends Declared Per Share		$ 28.25	$ 28.25	$ 56.50	$ 56.50
Series B Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Liquidation Preference Per Share		$ 25,000		$ 25,000
Preferred Stock, Shares Outstanding		20,000		20,000
Dividends Declared Per Share		$ 406.25	$ 406.25	$ 1,625	$ 1,674.65
Series B-1 Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding		20,000		20,000
Preferred Stock
Class of Stock [Line Items]
Shares outstanding	[1]	$ 880	$ 880	$ 880	$ 880	$ 880	880	$ 880	$ 880
Preferred Stock | Series A Preferred Stock
Class of Stock [Line Items]
Shares outstanding		393.9		393.9			393.9
Preferred Stock | Series B Preferred Stock
Class of Stock [Line Items]
Shares outstanding		$ 486.1		$ 486.1			$ 486.1
[1]	(1) Series A and Series B shares have an aggregate liquidation preference of $400M and $500M, respectively. See Note 5, "Equity" for additional information.

Assets and Liabilities Held f_3

Assets and Liabilities Held for Sale (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Oct. 09, 2020	Feb. 26, 2020
Disposal Groups [Line Items]
Purchase Price						$ 1,100
Loss on classification as held for sale	$ 35.6	$ 0	$ 400.2	$ 0
Subsequent Event
Disposal Groups [Line Items]
Net Proceeds from Sale					$ 1,112.6

Assets and Liabilities Held f_4

Assets and Liabilities Held for Sale (Tables) (Details) - USD ($) $ in Millions		3 Months Ended
		Sep. 30, 2020	Dec. 31, 2019
Assets and Liabilities Held for Sale [Line Items]
Assets held for sale		$ 1,565.7	$ 0
Liabilities held for sale		451.8	$ 0
Massachusetts Business
Assets and Liabilities Held for Sale [Line Items]
Assets Held for Sale Net Property, Plant and Equipment		1,705
Assets Held for Sale Total Current Assets		161.5
Assets Held for Sale Total Other Assets		91.8
Gain (Loss) on Sale of Assets and Asset Impairment Charges	[1]	(392.6)
Assets held for sale		1,565.7
Liabilities Held for Sale Long Term Debt		41.6
Liabilities Held for Sale Total Current Liabilities		60.1
Liabilities Held for Sale Total Other Liabilities		350.1
Liabilities held for sale		$ 451.8
[1]	(1) Amount differs from that presented in the Condensed Statements of Consolidated Income (Loss) (unaudited) due to cash already paid for certain transaction costs.

Assets and Liabilities Held f_5

Assets and Liabilities Held for Sale Pretax Income (Tables) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Massachusetts Business
Assets and Liabilities Held for Sale Pretax Income [Line Items]
Disposal Group, Including Discontinued Operation, Operating Income (Loss)	$ (74.1)	$ (55.2)	$ (402.9)	$ 183.5

Property, Plant, and Equipment

Property, Plant, and Equipment (Details) $ in Millions	Sep. 30, 2020USD ($)
Property, Plant and Equipment [Abstract]
Plant and Equipment associated with Schahfer Generating Station Retirement	$ 903.8

Asset Retirement Obligations As

Asset Retirement Obligations Asset Retirement Obligations (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Asset Retirement Obligation Disclosure [Abstract]
Assets recorded for asset retirement obligations	$ 70.3	$ 12.8

Regulatory Matters Narrative (D

Regulatory Matters Narrative (Details) $ in Millions	Sep. 30, 2020USD ($)
Incremental O&M - COVID | Columbia Of Ohio
Regulated Operations
Regulatory Assets	$ 1.9
Incremental O&M and Bad Debt - COVID | NIPSCO
Regulated Operations
Regulatory Assets	4.8
Incremental O&M and Bad Debt - COVID | Columbia Of Maryland
Regulated Operations
Regulatory Assets	0.5
Incremental Bad Debt - COVID | Columbia Of Pennsylvania
Regulated Operations
Regulatory Assets	$ 1.3

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Regulatory Programs) (Details) - USD ($) $ in Millions

Oct. 29, 2020

Oct. 15, 2020

Sep. 29, 2020

Sep. 18, 2020

Aug. 25, 2020

Jul. 24, 2020

Jun. 19, 2020

May 26, 2020

May 15, 2020

Apr. 27, 2020

Apr. 24, 2020

Apr. 15, 2020

Feb. 28, 2020

Feb. 25, 2020

Jan. 29, 2020

Nov. 26, 2019

Oct. 18, 2019

Oct. 15, 2019

Aug. 21, 2019

Aug. 15, 2019

Oct. 31, 2018

Columbia Of Ohio | 2020 IRP

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 32.9

Regulatory Net Capital Expenditures Included In Filing

234.4

Columbia Of Ohio | 2020 CEP

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

18

Regulatory Net Capital Expenditures Included In Filing

$ 185.1

NIPSCO - Gas | TDSIC 11

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[1]

$ (1.7)

Regulatory Net Capital Expenditures Included In Filing

[1]

$ 38.7

NIPSCO - Gas | FMCA 3

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[2]

$ 0.3

Regulatory Net Capital Expenditures Included In Filing

[2]

$ 43

NIPSCO - Gas | FMCA 4

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[2]

$ 1.6

Regulatory Net Capital Expenditures Included In Filing

[2]

$ 43.2

NIPSCO - Gas | TDSIC 1

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 1.3

Regulatory Net Capital Expenditures Included In Filing

$ 26

Columbia Of Virginia | 2020 SAVE

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 3.8

Regulatory Net Capital Expenditures Included In Filing

$ 50

Columbia Of Virginia | 2021 SAVE

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 5.2

Regulatory Net Capital Expenditures Included In Filing

$ 46.4

Columbia Of Kentucky | 2020 SMRP

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 4.2

Regulatory Net Capital Expenditures Included In Filing

$ 40.4

Columbia Of Maryland

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 2

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 5

Columbia Of Maryland | 2020 STRIDE

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 1.3

Regulatory Net Capital Expenditures Included In Filing

$ 15

NIPSCO - Electric

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ (53.5)

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 21.4

NIPSCO - Electric | TDSIC 6

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 28.1

Regulatory Net Capital Expenditures Included In Filing

$ 131.1

NIPSCO - Electric | FMCA 12

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[2]

$ 1.6

Regulatory Net Capital Expenditures Included In Filing

[2]

$ 4.7

NIPSCO - Electric | FMCA 13

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[2],[3]

$ (1.2)

Regulatory Net Capital Expenditures Included In Filing

[2],[3]

$ 0

NIPSCO - Electric | TDSIC 7

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 13

Regulatory Net Capital Expenditures Included In Filing

$ 122.3

Columbia Of Pennsylvania

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 100.4

Columbia Of Pennsylvania | DSIC

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 0.9

Regulatory Net Capital Expenditures Included In Filing

$ 28.2

Columbia Of Pennsylvania | DSIC Q2 2020

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 0.8

Regulatory Net Capital Expenditures Included In Filing

$ 28.6

Columbia Of Pennsylvania | DSIC Q3 2020

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 2.6

Regulatory Net Capital Expenditures Included In Filing

$ 85

Subsequent Event | Columbia Of Kentucky | 2021 SMRP

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 5.8

Regulatory Net Capital Expenditures Included In Filing

$ 50

Subsequent Event | Columbia Of Maryland | 2021 STRIDE

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 1.3

Regulatory Net Capital Expenditures Included In Filing

$ 16.9

[1]

(2) Incremental revenue is net of amounts included in the step 2 rates and reflects a more typical 6-month filing period.

[2]

(3) Incremental revenue is inclusive of tracker eligible operations and maintenance expense.

[3]

(4) No eligible capital investments were made during the investment period.

Regulatory Matters (Rate Case A

Regulatory Matters (Rate Case Action) (Details) - USD ($) $ in Millions	May 15, 2020	Apr. 24, 2020	Oct. 31, 2018
NIPSCO - Electric
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount			$ 21.4
Public Utilities, Approved Rate Increase (Decrease), Amount			$ (53.5)
Columbia Of Maryland
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	$ 5
Public Utilities, Approved Rate Increase (Decrease), Amount	$ 2
Columbia Of Pennsylvania
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 100.4

Risk Management Activities (Nar

Risk Management Activities (Narrative) (Details) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative [Line Items]
Limit of GCA Volumes	20.00%
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ 0	$ 0	$ 0
Interest Rate Swap
Derivative [Line Items]
Derivative, Notional Amount	$ 500,000,000
Minimum
Derivative [Line Items]
Commodity Contract Length	5 years
Maximum
Derivative [Line Items]
Commodity Contract Length	10 years

Risk Management Activities (Sch

Risk Management Activities (Schedule of Derivative Instruments in Statement of Financial Position, Fair Value) (Details) - USD ($) $ in Millions		Sep. 30, 2020	Dec. 31, 2019
Risk Management Assets Current
Derivatives, Fair Value [Line Items]
Risk management assets	[1]	$ 13.7	$ 0.6
Risk Management Assets Noncurrent
Derivatives, Fair Value [Line Items]
Risk management assets	[2]	6.7	3.8
Risk Management Liabilities Current
Derivatives, Fair Value [Line Items]
Risk management liabilities		96.9	12.6
Risk Management Liabilities Noncurrent
Derivatives, Fair Value [Line Items]
Risk management liabilities		169.5	134
Interest Rate Risk | Risk Management Assets Current
Derivatives, Fair Value [Line Items]
Risk management assets	[1]	0	0
Interest Rate Risk | Risk Management Assets Noncurrent
Derivatives, Fair Value [Line Items]
Risk management assets	[2]	0	0
Interest Rate Risk | Risk Management Liabilities Current
Derivatives, Fair Value [Line Items]
Risk management liabilities		92.1	0
Interest Rate Risk | Risk Management Liabilities Noncurrent
Derivatives, Fair Value [Line Items]
Risk management liabilities		123.3	76.2
Commodity Price Risk Programs | Risk Management Assets Current
Derivatives, Fair Value [Line Items]
Risk management assets	[1]	13.7	0.6
Commodity Price Risk Programs | Risk Management Assets Noncurrent
Derivatives, Fair Value [Line Items]
Risk management assets	[2]	6.7	3.8
Commodity Price Risk Programs | Risk Management Liabilities Current
Derivatives, Fair Value [Line Items]
Risk management liabilities		4.8	12.6
Commodity Price Risk Programs | Risk Management Liabilities Noncurrent
Derivatives, Fair Value [Line Items]
Risk management liabilities		$ 46.2	$ 57.8
[1]	Presented in "Prepayments and other" on the Condensed Consolidated Balance Sheets (unaudited).
[2]	Presented in "Deferred charges and other" on the Condensed Consolidated Balance Sheets (unaudited).

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value Disclosure [Line Items]
Transfers between Fair Value Hierarchies			$ 0		$ 0
Material Level 3 Changes			0		0
Allowance for Credit Loss	$ (0.7)		(0.7)		$ 0
Loss on classification as held for sale	35.6	$ 0	400.2	$ 0
U.S. Treasury debt securities
Fair Value Disclosure [Line Items]
Available-for-sale Securities, Maturities, Next Twelve Months, Fair Value	7		7
Corporate/Other debt securities
Fair Value Disclosure [Line Items]
Available-for-sale Securities, Maturities, Next Twelve Months, Fair Value	$ 5.8		$ 5.8

Fair Value (Fair Value Of Finan

Fair Value (Fair Value Of Financial Assets And Liabilities Measured On A Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets
Total	$ 182.2	$ 158.6
Liabilities
Total	266.4	146.6
Fair Value, Inputs, Level 1
Assets
Risk management assets	0	0
Available-for-sale securities	0	0
Total	0	0
Liabilities
Risk management liabilities	0	0
Total	0	0
Significant Other Observable Inputs (Level 2)
Assets
Risk management assets	20.4	4.4
Available-for-sale securities	161.8	154.2
Total	182.2	158.6
Liabilities
Risk management liabilities	266.4	146.6
Total	266.4	146.6
Significant Unobservable Inputs (Level 3)
Assets
Risk management assets	0	0
Available-for-sale securities	0	0
Total	0	0
Liabilities
Risk management liabilities	0	0
Total	0	0
Available-for-sale Securities
Assets
Available-for-sale securities	161.8	154.2
Risk management assets
Assets
Risk management assets	20.4	4.4
Liabilities
Risk management liabilities	$ 266.4	$ 146.6

Fair Value (Available-For-Sale

Fair Value (Available-For-Sale Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2020		Dec. 31, 2019
Fair Value Disclosure [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 0		$ 17.2
Amortized Cost	156.1		150.1
Gross Unrealized Gains	7.4		4.3
Gross Unrealized Losses	(1)	[1]	(0.2)	[2]
Allowance for Credit Loss	(0.7)		0
Fair Value	161.8		154.2
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	20.4		12.2
U.S. Treasury debt securities
Fair Value Disclosure [Line Items]
Amortized Cost	31.5		31.4
Gross Unrealized Gains	0.4		0.1
Gross Unrealized Losses	0	[1]	(0.1)	[2]
Fair Value	31.9		31.4
Corporate/Other debt securities
Fair Value Disclosure [Line Items]
Amortized Cost	124.6		118.7
Gross Unrealized Gains	7		4.2
Gross Unrealized Losses	(1)	[1]	(0.1)	[2]
Fair Value	$ 129.9		$ 122.8
[1]	(1) Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $0 and $20.4 million, respectively, at September 30, 2020.
[2]	(2) Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $17.2 million and $12.2 million, respectively, at December 31, 2019.

Fair Value (Carrying Amount And

Fair Value (Carrying Amount And Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Long-term Debt (including current portion), Carrying Amount	$ 9,230.3	$ 7,869.6
Long-term debt (including current portion), Estimated Fair Value	$ 10,723.5	$ 8,764.4

Transfers Of Financial Assets_2

Transfers Of Financial Assets (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Number of Agreements			3
Cash From Financing Activities Related To The Change In Short-Term Borrowings Due To The Securitization Transactions			$ 122	$ 139.1
Securitization Transaction Fees	$ 0.6	$ 0.6	2.1	$ 2
Accounts Receivable Program
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Seasonal Limit	$ 275		$ 275

Transfers Of Financial Assets_3

Transfers Of Financial Assets (Schedule Of Gross And Net Receivables Transferred As Well As Short-Term Borrowings Related To The Securitization Transactions) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Gross Receivables	$ 421.7	$ 569.1
Less: Receivables not transferred	190.5	215.9
Net receivables transferred	231.2	353.2
Accounts receivable securitization facility borrowings	$ 231.2	$ 353.2

Goodwill (Narrative) (Details)

Goodwill (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill	$ 1,485.9	$ 1,485.9
Columbia Of Massachusetts
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 204.8

Goodwill (Schedule of Goodwill)

Goodwill (Schedule of Goodwill) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Goodwill [Line Items]
Goodwill	$ 1,485.9	$ 1,485.9
Gas Distribution Operations
Goodwill [Line Items]
Goodwill	1,485.9
Electric Operations
Goodwill [Line Items]
Goodwill	0
Corporate and Other
Goodwill [Line Items]
Goodwill	$ 0

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Effective income tax rates	27.30%	283.30%	42.00%	18.80%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate			21.00%
Increase (Decrease) in Effective Tax Rate	(256.00%)		23.20%
Changes to Liability for Uncertain Tax Positions			$ 0
Deferred Payroll Taxes	$ 21.7		$ 21.7

Pension And Other Postretirem_3

Pension And Other Postretirement Benefits (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 2.1
Defined Benefit Plan, Pension Asset, (Increase)Decrease For Remeasurement Due To Settlement	(6.1)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement	(0.2)
Change in Regulatory Assets Due to Interim Measurement	1.4
Change in Accumulated Other Comprehensive Income Due to Interim Measurement	0.2
Change to Defined Benefit Plan Net Periodic Costs Due to Interim Measurement	(1.4)
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 16.7

Pension And Other Postretirem_4

Pension And Other Postretirement Benefits (Components Of The Plans' Net Periodic Benefits Cost) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	[1]	$ 8.1	$ 7.3	$ 24.1	$ 21.9
Interest cost	[1]	13.1	18.1	40.1	54.5
Expected return on assets	[1]	(28.3)	(27.2)	(85.1)	(81.6)
Amortization of prior service credit	[1]	0.2	0	0.6	0
Recognized actuarial loss	[1]	8.6	11.3	26	34.1
Settlement loss	[1]	(8)	(1.9)	(8)	(1.9)
Total Net Periodic Benefits Cost		9.7	11.4	13.7	30.8
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	[1]	1.7	1.3	4.9	3.9
Interest cost	[1]	3.8	4.8	11.6	14.4
Expected return on assets	[1]	(3.6)	(3.3)	(10.8)	(9.9)
Amortization of prior service credit	[1]	(0.4)	(0.8)	(1.4)	(2.4)
Recognized actuarial loss	[1]	1.2	0.5	3.8	1.5
Settlement loss	[1]	0	0	0	0
Total Net Periodic Benefits Cost		$ 2.7	$ 2.5	$ 8.1	$ 7.5
[1]	(1) The service cost component and all non-service cost components of net periodic benefit cost are presented in "Operation and maintenance" and "Other, net", respectively, on the Condensed Statements of Consolidated Income (Loss) (unaudited).

Pension And Other Postretirem_5

Pension And Other Postretirement Benefits Schedule of Assumptions Used (Details) - Pension Plan	9 Months Ended
	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.28%
Discount rate- service cost	3.39%
Discount rate - interest cost	2.65%
Expected return on assets	5.20%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Aug. 31, 2020	Aug. 18, 2020	Apr. 13, 2020
Debt Instrument [Line Items]
Debt Instrument Tendered			$ 969.3
Gain (Loss) on Extinguishment of Debt	$ (243.4)	$ 0	(243.4)	$ 0
Working Capital Adjustment	$ 5.3		$ 5.3
3.60% Notes Due 2030 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.60%		3.60%
0.95% Notes Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						0.95%
1.70% Notes Due 2031 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						1.70%
4.45% Notes Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.45%		4.45%		4.45%
2.65% Notes Due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.65%		2.65%		2.65%
3.85% Notes Due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.85%		3.85%		3.85%
3.65% Notes Due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.65%		3.65%		3.65%
6.25% Notes Due 2040 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					6.25%
5.95% Notes Due 2041 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					5.95%
Senior Note Redeemed August & September 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount	$ 609.3		$ 609.3
Gain (Loss) on Extinguishment of Debt	$ 231.7
5.89% Notes Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.89%		5.89%
Note Redeemed September 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount	$ 25		$ 25
Gain (Loss) on Extinguishment of Debt	$ 11.7
6.26% Notes Due 2028 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					6.26%
Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount							$ 1,000
Senior Notes | 3.60% Notes Due 2030 [Member]
Debt Instrument [Line Items]
Proceeds from Debt, Net of Issuance Costs			987.8
Senior Notes | 0.95% Notes Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount						$ 1,250
Senior Notes | 1.70% Notes Due 2031 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount						$ 750
Senior Notes | 0.95% Notes Due 2025 and 1.70% Notes Due 2031 [Member]
Debt Instrument [Line Items]
Proceeds from Debt, Net of Issuance Costs			$ 1,980.4

Short-Term Borrowings (Narrativ

Short-Term Borrowings (Narrative) (Details) - USD ($) $ in Millions	Apr. 01, 2020	Sep. 30, 2020	Dec. 31, 2019	Apr. 17, 2019
Short-term Debt [Line Items]
Commercial paper outstanding		$ 307	$ 570
Accounts receivable securitization facility borrowings		231.2	353.2
Revolving Credit Facility
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,850
Long-term Line of Credit			0
Commercial Paper
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,500
Term Loan
Short-term Debt [Line Items]
Term Loan		$ 850	$ 850
Debt Instrument, Basis Spread on Variable Rate	0.75%
Maximum | Term Loan
Short-term Debt [Line Items]
Term Loan	$ 850			$ 850

Short-Term Borrowings (Schedule

Short-Term Borrowings (Schedule Of Short-Term Borrowings) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Short-term Debt [Line Items]
Commercial paper weighted-average interest rate of 0.23% and 2.03% at September 30, 2020 and December 31, 2019, respectively	$ 307	$ 570
Accounts receivable securitization facility borrowings	231.2	353.2
Total short-term borrowings	$ 1,388.2	1,773.2
Revolving Credit Facility
Short-term Debt [Line Items]
Revolving credit facility interest rate of 2.13% at March 31, 2020		$ 0
Commercial Paper
Short-term Debt [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	0.23%	2.03%
Term Loan
Short-term Debt [Line Items]
Term loan interest rate of 0.90% and 2.40% at September 30, 2020 and December 31, 2019, respectively	$ 850	$ 850
Short-term Debt, Weighted Average Interest Rate, at Point in Time	0.90%	2.40%

Other Commitments And Conting_3

Other Commitments And Contingencies (Narrative) (Details)	3 Months Ended	4 Months Ended	9 Months Ended	16 Months Ended	25 Months Ended
	Sep. 30, 2020USD ($)RateMW	Dec. 31, 2018USD ($)	Sep. 30, 2020USD ($)RateMW	Dec. 31, 2019USD ($)	Sep. 30, 2020USD ($)RateMW	Oct. 16, 2020MW	Oct. 09, 2020	Oct. 31, 2019MW	Jul. 26, 2019USD ($)	Jan. 01, 2019RateMW
Other Commitments And Contingencies [Line Items]
Guaranty Liabilities	$ 195,600,000		$ 195,600,000		$ 195,600,000
Litigation Settlement, Amount Awarded to Other Party									$ 143,000,000
Expenses Related to Third-Party Claims	(3,000,000)		(5,000,000)	$ 1,041,000,000	1,036,000,000
Liability Insurance for Damages	800,000,000		800,000,000		800,000,000
Proceeds From Insurance Settlement					800,000,000
Recorded reserves to cover environmental remediation at various sites	93,400,000		$ 93,400,000	104,400,000	93,400,000
Coal-fired Generating Capacity | MW			2,080
Coal-fired Generating Capacity, Percent of Total Capacity | Rate			72.00%
Coal-fired Generating Capacity, Percent of Total Coal-Fired Capacity | Rate			100.00%
Liability Associated with Schahfer Generating Station Retirement	$ 4,600,000		$ 4,600,000		$ 4,600,000
Wind Power Purchase Agreement, Purchase Percentage | Rate	100.00%		100.00%		100.00%					100.00%
Planned Replacement Capacity | MW	1,400		1,400		1,400
Other incident-related costs	$ 5,000,000		$ 21,000,000	420,000,000	$ 441,000,000
Costs Resulting from the Greater Lawrence Incident	2,000,000	$ 1,023,000,000	16,000,000	1,461,000,000	1,477,000,000
Restructuring and Related Cost, Expected Cost	$ 38,000,000		38,000,000		$ 38,000,000
Other Restructuring Costs			$ 23,400,000
MGP Sites
Other Commitments And Contingencies [Line Items]
Number of waste disposal sites identified by program	63		63		63
Liability for Estimated Remediation Costs	$ 88,300,000		$ 88,300,000	102,200,000	$ 88,300,000
Reasonably possible remediation costs variance from reserve	20,000,000		$ 20,000,000		20,000,000
Columbia Of Massachusetts
Other Commitments And Contingencies [Line Items]
Gas Meters Affected			7,500
Businesses Impacted by Incident			700
Settlement Agreement Payment in Lieu of Penalties			$ 56,000,000
Plea Agreement Criminal Fine			$ 53,030,116
Miles of Affected Cast Iron and Bare Steel Pipeline System			45
Pipeline Replacement Expenses					258,000,000
Deferred Tax Assets, Net	50,000,000		$ 50,000,000		50,000,000
NIPSCO
Other Commitments And Contingencies [Line Items]
Estimated Cost of Compliance with Effluent Limitations Guidelines			170,000,000
Maximum | Columbia Of Massachusetts
Other Commitments And Contingencies [Line Items]
Civil Penalty Assessed for Violation of Federal Pipeline Safety Regulations			218,647
Civil Penalty Assessed for Series of Violations of Federal Pipeline Safety Regulations			2,200,000
Penalty Per Violation of Emergency Response Plan			250,000
Penalty for Violations of Emergency Response Plan			20,000,000
Penalty Per Violation of Operational Directives During Restoration Efforts			1,000,000
Expenses Related to Third-Party Claims					1,050,000,000
Other incident-related costs					455,000,000
Minimum | Columbia Of Massachusetts
Other Commitments And Contingencies [Line Items]
Expenses Related to Third-Party Claims					1,036,000,000
Other incident-related costs					445,000,000
Standby Letters of Credit
Other Commitments And Contingencies [Line Items]
Long-term Line of Credit	$ 10,200,000		$ 10,200,000	$ 10,200,000	$ 10,200,000
Subsequent Event | MGP Sites
Other Commitments And Contingencies [Line Items]
Number of waste disposal sites identified by program							54
Purchase Power Agreements - Jun 2020 [Member]
Other Commitments And Contingencies [Line Items]
Long-term Purchase Commitment, Period			20 years
Nameplate Capacity | MW	500		500		500
Storage Capacity | MW	30		30		30
Build Transfer Agreement [Member]
Other Commitments And Contingencies [Line Items]
Nameplate Capacity | MW								300		100
Build Transfer Agreement [Member] | Subsequent Event
Other Commitments And Contingencies [Line Items]
Nameplate Capacity | MW						900
Storage Capacity | MW						135
Build Transfer Agreement [Member] | Subsequent Event | 2023 [Member]
Other Commitments And Contingencies [Line Items]
Nameplate Capacity | MW						635
Build Transfer Agreement [Member] | Subsequent Event | 2022 [Member]
Other Commitments And Contingencies [Line Items]
Nameplate Capacity | MW						265
Purchase Power Agreements - Jan 2019 [Member]
Other Commitments And Contingencies [Line Items]
Long-term Purchase Commitment, Period			20 years
Nameplate Capacity | MW										400

Other Commitments And Conting_4

Other Commitments And Contingencies Other Commitments and Contingencies (Expense and Insurance Recoveries) (Details) - USD ($) $ in Millions	3 Months Ended	4 Months Ended	9 Months Ended	16 Months Ended	25 Months Ended
	Sep. 30, 2020	Dec. 31, 2018	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2020
Expense and Insurance Recoveries [Line Items]
Third-party claims	$ (3)		$ (5)	$ 1,041	$ 1,036
Other incident-related costs	5		21	420	441
Total	2	$ 1,023	16	1,461	1,477
Insurance recoveries recorded	0		0	(800)	(800)
Total costs incurred	$ 2		$ 16	$ 661	$ 677

Other Commitments And Conting_5

Other Commitments And Contingencies Other Commitments and Contingencies (Insurance Recoveries and Cash Collected (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	16 Months Ended	25 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Insurance recoveries recorded	$ 0	$ 0	$ 800	$ 800
Cash collected from insurance recoveries				$ (800)

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Components Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	$ (221.9)	$ (80.8)	$ (92.6)	$ (37.2)
Other Comprehensive Income before reclassifications	[1]	28.2	(49.6)	(101.2)	(93.9)
Amounts reclassified from accumulated other comprehensive loss	[1]	0.1	0.1	0.2	0.8
Net current-period other comprehensive income (loss)	[1]	28.3	(49.5)	(101)	(93.1)
Ending Balance	[1]	(193.6)	(130.3)	(193.6)	(130.3)
Gains and Losses on Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	3.6	2.5	3.3	(2.4)
Other Comprehensive Income before reclassifications	[1]	1.2	0.9	2	5.9
Amounts reclassified from accumulated other comprehensive loss	[1]	0.2	(0.2)	(0.3)	(0.3)
Net current-period other comprehensive income (loss)	[1]	1.4	0.7	1.7	5.6
Ending Balance	[1]	5	3.2	5	3.2
Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	(207.8)	(62.8)	(77.2)	(13)
Other Comprehensive Income before reclassifications	[1]	26	(50.7)	(104.6)	(100.5)
Amounts reclassified from accumulated other comprehensive loss	[1]	0	0.1	0	0.1
Net current-period other comprehensive income (loss)	[1]	26	(50.6)	(104.6)	(100.4)
Ending Balance	[1]	(181.8)	(113.4)	(181.8)	(113.4)
Pension and OPEB Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	(17.7)	(20.5)	(18.7)	(21.8)
Other Comprehensive Income before reclassifications	[1]	1	0.2	1.4	0.7
Amounts reclassified from accumulated other comprehensive loss	[1]	(0.1)	0.2	0.5	1
Net current-period other comprehensive income (loss)	[1]	0.9	0.4	1.9	1.7
Ending Balance	[1]	$ (16.8)	$ (20.1)	$ (16.8)	$ (20.1)
[1]	All amounts are net of tax. Amounts in parentheses indicate debits.

Other, Net (Details)

Other, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other, Net [Abstract]
Interest income	$ 1.3	$ 2.1	$ 4.4	$ 5.4
AFUDC equity	1.8	2.9	4.9	7.1
Charitable Contributions	(0.3)	(1.1)	(0.9)	(4)
Pension and other postretirement non-service cost	0.6	(2.8)	6.4	(8.7)
Sale of emission reduction credits	4.6	0	4.6	0
Miscellaneous	0	0.2	0.5	0.5
Other, net	$ 8	$ 1.3	$ 19.9	$ 0.3

Business Segment Information (N

Business Segment Information (Narrative) (Details)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Primary business segments	2
Number of counties in which electric service provided by Electric Operations	20

Business Segment Information (S

Business Segment Information (Schedule Of Operating Income Derived From Revenues And Expenses By Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 902.5	$ 931.5	$ 3,470.7	$ 3,811.7
Consolidated Operating Income (Loss)	92.8	91	332.7	928.7
Gas Distribution Operations
Segment Reporting Information [Line Items]
Revenues	473.1	466.9	2,313.4	2,516.1
Consolidated Operating Income (Loss)	(42.2)	(48.6)	38	605.8
Gas Distribution Operations | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	470.1	463.6	2,304.4	2,506.2
Gas Distribution Operations | Intersegment
Segment Reporting Information [Line Items]
Revenues	3	3.3	9	9.9
Electric Operations
Segment Reporting Information [Line Items]
Revenues	432.3	467.9	1,166.2	1,305.5
Consolidated Operating Income (Loss)	130	140.7	295.4	321.4
Electric Operations | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	432.2	467.7	1,165.7	1,304.9
Electric Operations | Intersegment
Segment Reporting Information [Line Items]
Revenues	0.1	0.2	0.5	0.6
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	120.7	117.1	328.5	342.8
Consolidated Operating Income (Loss)	5	(1.1)	(0.7)	1.5
Corporate and Other | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	0.2	0.2	0.6	0.6
Corporate and Other | Intersegment
Segment Reporting Information [Line Items]
Revenues	120.5	116.9	327.9	342.2
Eliminations
Segment Reporting Information [Line Items]
Revenues	$ (123.6)	$ (120.4)	$ (337.4)	$ (352.7)