NiSource (NI) 10-Q 30 Oct 19 2019 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 23, 2019
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
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		373,542,659
Entity Central Index Key	0001111711
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating Revenues
Customer revenues	[1]	$ 891	$ 855.8	$ 3,694.7	$ 3,555.1
Other revenues		40.5	39.2	117	97.7
Total Operating Revenues		931.5	895	3,811.7	3,652.8
Operating Expenses
Cost of Sales (excluding depreciation and amortization)		196.7	222	1,130.5	1,259.7
Operation and maintenance		393.9	780.8	995.5	1,548.5
Depreciation and amortization		182.2	148.5	535.2	437.8
Loss (Gain) on sale of assets and impairments, net		(0.2)	0.7	(0.1)	0.4
Other taxes		67.9	58.9	221.9	203.3
Total Operating Expenses		840.5	1,210.9	2,883	3,449.7
Operating Income (Loss)		91	(315.9)	928.7	203.1
Other Income (Deductions)
Interest expense, net		(95.9)	(83.4)	(285.6)	(265.2)
Other, net		1.3	(1.7)	0.3	42.4
Loss on early extinguishment of long-term debt		0	(33)	0	(45.5)
Total Other Deductions, Net		(94.6)	(118.1)	(285.3)	(268.3)
Income (Loss) before Income Taxes		(3.6)	(434)	643.4	(65.2)
Income Taxes		(10.2)	(94.5)	121	(26.3)
Net Income (Loss)		6.6	(339.5)	522.4	(38.9)
Preferred dividends		(13.8)	(5.6)	(41.4)	(6.9)
Net Income (Loss) Available to Common Shareholders		$ (7.2)	$ (345.1)	$ 481	$ (45.8)
Earnings (Loss) Per Share
Basic Earnings (Loss) Per Share		$ (0.02)	$ (0.95)	$ 1.29	$ (0.13)
Diluted Earnings (Loss) Per Share		$ (0.02)	$ (0.95)	$ 1.28	$ (0.13)
Basic Average Common Shares Outstanding		374,100	363,900	373,796	352,100
Diluted Average Common Shares		374,100	363,900	375,195	352,100
[1]	Customer revenue amounts exclude intersegment revenues. See Note 19

Statements of Consolidated Comp

Statements of Consolidated Comprehensive Income (Loss) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net Income (Loss)		$ 6.6	$ (339.5)	$ 522.4	$ (38.9)
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale securities	[1]	0.7	0.1	5.6	(2.3)
Net unrealized gain (loss) on cash flow hedges	[2]	(50.6)	22.5	(100.4)	56.5
Unrecognized pension and OPEB benefit	[3]	0.4	0.8	1.7	1.2
Total other comprehensive income (loss)	[4]	(49.5)	23.4	(93.1)	55.4
Comprehensive Income (Loss)		$ (42.9)	$ (316.1)	$ 429.3	$ 16.5
[1]	Net unrealized gain (loss) on available-for-sale securities, net of $0.1 million and zero tax expense in the third quarter of 2019 and 2018 , respectively, and $1.4 million tax expense and $0.6 million tax benefit for the nine months ended 2019 and 2018 , respectively.
[2]	Net unrealized gain (loss) on cash flow hedges, net of $16.7 million tax benefit and $7.5 million tax expense in the third quarter of 2019 and 2018 , respectively, and $33.2 million tax benefit and $18.7 million tax expense for the nine months ended 2019 and 2018 , respectively.
[3]	Unrecognized pension and OPEB benefit, net of $0.1 million and zero tax expense in the third quarter of 2019 and 2018 , and $0.6 million and $0.2 million tax expense for the nine months ended 2019 and 2018 , 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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, Tax	$ 0.1	$ 0	$ 1.4	$ (0.6)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(16.7)	7.5	(33.2)	18.7
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	$ (0.1)	$ 0	$ (0.6)	$ (0.2)

Statements of Consolidated Bala

Statements of Consolidated Balance Sheets - USD ($) $ in Millions		Sep. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment
Utility Plant		$ 24,026.1	$ 22,780.8
Accumulated depreciation and amortization		(7,563.2)	(7,257.9)
Net utility plant		16,462.9	15,522.9
Other property, at cost, less accumulated depreciation		18	19.6
Net Property, Plant and Equipment		16,480.9	15,542.5
Investments and Other Assets
Unconsolidated affiliates		2.2	2.1
Other investments		217.5	204
Total Investments and Other Assets		219.7	206.1
Current Assets
Cash and cash equivalents		28	112.8
Restricted Cash		9	8.3
Accounts receivable (less reserve of $15.1 and $21.1, respectively)		539.3	1,058.5
Gas inventory		294.9	286.8
Materials and supplies, at average cost		115.1	101
Electric production fuel, at average cost		38.7	34.7
Exchange gas receivable		30.3	88.4
Regulatory assets		237.6	235.4
Prepayments and other		85.4	129.5
Total Current Assets		1,378.3	2,055.4
Other Assets
Regulatory assets		1,993.2	2,002.1
Goodwill		1,690.7	1,690.7
Intangible assets, net		212.5	220.7
Deferred charges and other		157	86.5
Total Other Assets		4,053.4	4,000
Total Assets		22,132.3	21,804
Stockholders' Equity
Common stock - $0.01 par value, 600,000,000 shares authorized; 373,446,862 and 372,363,656 shares outstanding, respectively		3.8	3.8
Preferred stock - $0.01 par value, 20,000,000 shares authorized; 440,000 and 420,000 shares outstanding, respectively		880	880
Treasury stock		(99.9)	(99.9)
Additional paid-in capital		6,426.5	6,403.5
Retained deficit		(1,231.6)	(1,399.3)
Accumulated other comprehensive loss	[1]	(130.3)	(37.2)
Total Stockholders' Equity		5,848.5	5,750.9
Long-term debt, excluding amounts due within one year		7,853.8	7,105.4
Total Capitalization		13,702.3	12,856.3
Current Liabilities
Current portion of long-term debt		10.9	50
Short-term borrowings		1,615.1	1,977.2
Accounts payable		494.9	883.8
Dividends payable - common stock		74.7	0
Dividends payable - preferred stock		19.4	0
Customer deposits and credits		242.8	238.9
Taxes accrued		157.8	222.7
Interest accrued		95.6	90.7
Exchange gas payable		54.8	85.5
Regulatory liabilities		103	140.9
Legal and environmental		20	18.9
Accrued compensation and employee benefits		145.7	149.7
Claims accrued		184.3	114.7
Other accruals		120.7	63.8
Total Current Liabilities		3,339.7	4,036.8
Other Liabilities
Risk management liabilities		125	46.7
Deferred income taxes		1,466.6	1,330.5
Deferred investment tax credits		10.1	11.2
Accrued insurance liabilities		85.3	84.4
Accrued liability for postretirement and postemployment benefits		365.5	389.1
Regulatory liabilities		2,440	2,519.1
Asset retirement obligations		373.1	352
Other noncurrent liabilities		224.7	177.9
Total Other Liabilities		5,090.3	4,910.9
Commitments and Contingencies		0	0
Total Capitalization and Liabilities		$ 22,132.3	$ 21,804
[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, 2019	Dec. 31, 2018
Accounts receivable less reserve	$ 15.1	$ 21.1
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	600,000,000	400,000,000
Common Stock, Shares, Outstanding	373,446,862	372,363,656
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	420,000

Statements Of Consolidated Cash

Statements Of Consolidated Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities
Net Income (Loss)	$ 522.4	$ (38.9)
Adjustments to Reconcile Net Income (Loss) to Net Cash from Operating Activities:
Loss on early extinguishment of debt	0	45.5
Depreciation and amortization	535.2	437.8
Deferred income taxes and investment tax credits	120.4	(26.4)
Other adjustments	18.8	15.6
Changes in Assets and Liabilities:
Components of working capital	146.8	442.9
Regulatory assets/liabilities	(70)	61.3
Deferred charges and other noncurrent assets	(76.4)	0.8
Other noncurrent liabilities	34.6	(11.4)
Net Cash Flows from Operating Activities	1,231.8	927.2
Investing Activities
Capital expenditures	(1,310)	(1,296.6)
Cost of removal	(84.5)	(72.6)
Purchases of available-for-sale securities	(104)	(71.4)
Sales of available-for-sale securities	104.1	58.5
Other investing activities	0.6	5.6
Net Cash Flows used for Investing Activities	(1,393.8)	(1,376.5)
Financing Activities
Issuance of long-term debt	750	350
Repayments of long-term debt and finance lease obligations	(48.5)	(1,044)
Premiums and other debt related costs	(11.9)	(46.1)
Issuance of short-term debt (maturity greater than 90 days)	600	600
Repayment of short-term debt (maturity greater than 90 days)	(550)	0
Change in short-term borrowings, net (maturity ≤ 90 days)	(412.1)	(194.6)
Issuance of common stock, net of issuance costs	10.9	611.6
Issuance of preferred stock, net of issuance costs	0	394.3
Acquisition of treasury stock	0	(4)
Dividends paid - common stock	(223.8)	(202.5)
Dividends paid - preferred stock	(36.7)	0
Net Cash Flows from Financing Activities	77.9	464.7
Change in cash, cash equivalents and restricted cash	(84.1)	15.4
Cash, cash equivalents and restricted cash at beginning of period	121.1	38.4
Cash, Cash Equivalents and Restricted Cash at End of Period	$ 37	$ 53.8

Statements Of Consolidated Ca_2

Statements Of Consolidated Cash Flows (Supplemental Disclosures of Cash Flow Information) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Supplemental Cash Flow [Abstract]
Capital expenditures included in current liabilities	$ 187.1	$ 167.5
Dividends declared but not paid	94.1	82.4
Reclassification of other property to regulatory assets	0	245.3
Assets recorded for asset retirement obligations	$ 12.8	$ 74.7

Statements Of Consolidated Equi

Statements Of Consolidated Equity - USD ($) $ in Millions	Total	Common Stock	Preferred Stock		Treasury Stock	Additional Paid-in Capital	Retained Deficit	Accumulated Other Comprehensive Income (Loss)
Dividends:
Cumulative effect of change in accounting principle | Accounting Standards Update 2018-02	$ 0	$ 0	$ 0	[1]	$ 0	$ 0	$ 9.5	$ (9.5)
Beginning balance at Dec. 31, 2017	4,320.1	3.4	0	[1]	(95.9)	5,529.1	(1,073.1)	(43.4)
Comprehensive Income:
Net Income (Loss)	(38.9)	0	0	[1]	0	0	(38.9)	0
Other comprehensive income (loss), net of tax	55.4	0	0	[1]	0	0	0	55.4
Dividends:
Common stock	(273.4)	0	0	[1]	0	0	(273.4)	0
Preferred stock	(11.6)	0	0	[1]	0	0	(11.6)	0
Treasury stock acquired	(4)	0	0	[1]	(4)	0	0	0
Stock Issuances:
Common Stock - private placement	599.6	0.3	0	[1]	0	599.3	0	0
Preferred stock	393.9	0	393.9	[1]	0	0	0	0
Employee stock purchase plan	4.2	0	0	[1]	0	4.2	0	0
Long-term incentive plan	11.5	0	0	[1]	0	11.5	0	0
401(k) and profit sharing	16.9	0	0	[1]	0	16.9	0	0
Ending balance at Sep. 30, 2018	5,073.7	3.7	393.9	[1]	(99.9)	6,161	(1,387.5)	2.5
Beginning balance at Jun. 30, 2018	5,463	3.7	394.4	[1]	(99.9)	6,151.2	(965.5)	(20.9)
Comprehensive Income:
Net Income (Loss)	(339.5)	0	0	[1]	0	0	(339.5)	0
Other comprehensive income (loss), net of tax	23.4	0	0	[1]	0	0	0	23.4
Dividends:
Common stock	(70.9)	0	0	[1]	0	0	(70.9)	0
Preferred stock	(11.6)	0	0	[1]	0	0	(11.6)	0
Stock Issuances:
Preferred stock	(0.5)	0	(0.5)	[1]	0	0	0	0
Employee stock purchase plan	1.5	0	0	[1]	0	1.5	0	0
Long-term incentive plan	3.3	0	0	[1]	0	3.3	0	0
401(k) and profit sharing	5	0	0	[1]	0	5	0	0
Ending balance at Sep. 30, 2018	5,073.7	3.7	393.9	[1]	(99.9)	6,161	(1,387.5)	2.5
Beginning balance at Dec. 31, 2018	5,750.9	3.8	880	[2]	(99.9)	6,403.5	(1,399.3)	(37.2)
Comprehensive Income:
Net Income (Loss)	522.4	0	0	[2]	0	0	522.4	0
Other comprehensive income (loss), net of tax	(93.1)	0	0	[2]	0	0	0	(93.1)
Dividends:
Common stock	(298.6)	0	0	[2]	0	0	(298.6)	0
Preferred stock	(56.1)	0	0	[2]	0	0	(56.1)	0
Stock Issuances:
Employee stock purchase plan	4.2	0	0	[2]	0	4.2	0	0
Long-term incentive plan	5.7	0	0	[2]	0	5.7	0	0
401(k) and profit sharing	13.1	0	0	[2]	0	13.1	0	0
Ending balance at Sep. 30, 2019	5,848.5	3.8	880	[2]	(99.9)	6,426.5	(1,231.6)	(130.3)
Beginning balance at Jun. 30, 2019	5,976.2	3.8	880	[2]	(99.9)	6,417.1	(1,144)	(80.8)
Comprehensive Income:
Net Income (Loss)	6.6	0	0	[2]	0	0	6.6	0
Other comprehensive income (loss), net of tax	(49.5)	0	0	[2]	0	0	0	(49.5)
Dividends:
Common stock	(74.8)	0	0	[2]	0	0	(74.8)	0
Preferred stock	(19.4)	0	0	[2]	0	0	(19.4)	0
Stock Issuances:
Employee stock purchase plan	1.5	0	0	[2]	0	1.5	0	0
Long-term incentive plan	3.6	0	0	[2]	0	3.6	0	0
401(k) and profit sharing	4.3	0	0	[2]	0	4.3	0	0
Ending balance at Sep. 30, 2019	$ 5,848.5	$ 3.8	$ 880	[2]	$ (99.9)	$ 6,426.5	$ (1,231.6)	$ (130.3)
[1]	Series A shares have an aggregate liquidation preference of $400M . See Note 5 , "Equity" for additional information.
[2]	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, 2017	337,016	0	340,813	(3,797)
Treasury Stock acquired	(166)	0	0	(166)
Issued:
Common stock private placement	24,964	0	24,964	0
Preferred stock	0	400	0	0
Employee stock purchase plan	166	0	166	0
Long-term incentive plan	499	0	499	0
401(k) and profit sharing	688	0	688	0
Ending balance at Sep. 30, 2018	363,167	400	367,130	(3,963)
Beginning balance at Jun. 30, 2018	362,915	400	366,878	(3,963)
Issued:
Employee stock purchase plan	55	0	55	0
Long-term incentive plan	5	0	5	0
401(k) and profit sharing	192	0	192	0
Ending balance at Sep. 30, 2018	363,167	400	367,130	(3,963)
Beginning balance at Dec. 31, 2018	372,363	420	376,326	(3,963)
Issued:
Preferred stock	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)

Statements Of Consolidated Eq_3

Statements Of Consolidated Equity (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Dividends Declared Per Share - Common	$ 0.200	$ 0.195	$ 0.800	$ 0.780
Series A Preferred Stock
Preferred Stock, Liquidation Preference, Value	$ 400	$ 400	$ 400	$ 400
Series B Preferred Stock
Preferred Stock, Liquidation Preference, Value	$ 500		$ 500

Basis of Accounting Presentatio

Basis of Accounting Presentation	9 Months Ended
	Sep. 30, 2019
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, 2018 . 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.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2019
New Accounting Pronouncements and Changes in Accounting Principles [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 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments The pronouncement clarifies and improves certain areas of guidance related to the recently issued standards on credit losses, hedging, and recognition and measurement. Topics 1, 2, and 5 of this update amends ASU 2016-13 as it relates to accrued interest, transfers between investment classifications, expected recoveries and reinsurance recoverables. Topic 3 improves guidance related to fair value hedges. Topic 4 of this update relates to codification improvements to ASU 2016-01. Annual periods beginning after December 15, 2019, including interim periods therein. Early adoption is permitted. We maintain investments in U.S. Treasury, corporate and mortgage-backed debt securities, which are pledged as collateral for trust accounts related to our wholly-owned insurance company. These debt securities are classified as available for sale ("AFS"). We are working with our external investment manager to enhance our current impairment model for AFS debt securities to comply with the standard. Upon adoption of ASC 326, we will recognize impairment for AFS debt securities by implementing an allowance approach instead of an 'other than temporary' impairment model. In addition, we have recorded balances for trade receivables that also fall within the scope of the standard. Based on shared risk characteristics, we segregated our trade receivables into 'residential customer receivables' and 'non-residential customer receivables'. We intend to apply separate models to calculate reserves for uncollectible receivables. While we continue to assess and enhance our processes of recording reserves for uncollectible receivables to comply with the current expected credit loss model, we do not expect any significant modifications to our current policy of calculating uncollectible reserves for our 'residential customer receivables' balances. ASC 326 also prescribes additional presentation and disclosure requirements. We are currently reviewing the impact of these requirements on our disclosures related to credit in our Notes to Condensed Consolidated Financial Statements (unaudited). We are unable to reasonably estimate the quantitative impact of adoption on our Condensed Consolidated Financial Statements (unaudited). We expect to adopt this ASU on its effective date. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326) The pronouncement changes the impairment model for most financial assets, replacing the current "incurred loss" model. ASU 2016-13 will require the use of an "expected loss" model for instruments measured at amortized cost. It will also require entities to record allowances for available-for-sale securities rather than impair the carrying amount of the securities. Subsequent improvements to the estimated credit losses of available-for-sale securities will be recognized immediately in earnings instead of over time as they are under historic guidance. 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 The 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 are currently evaluating the effects of this pronouncement on our Notes to Condensed Consolidated Financial Statements (unaudited). We expect to adopt this ASU on its effective date. Recently Adopted Accounting Pronouncements Standard Adoption ASU 2019-01, Leases (Topic 842): Codification Improvements See Note 15, "Leases," for our discussion of the effects of implementing these standards. ASU 2018-11, Leases (Topic 842): Targeted Improvements ASU 2018-01, Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842 ASU 2016-02, Leases (Topic 842)

Revenue Recognition

Revenue Recognition	9 Months Ended
	Sep. 30, 2019
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 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, 2019 and September 30, 2018: 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 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 19 , "Business Segment Information," for discussion of intersegment revenues. Three Months Ended September 30, 2018 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 257.0 $ 154.7 $ — $ 411.7 Commercial 80.9 140.7 — 221.6 Industrial 39.0 153.6 — 192.6 Off-system 20.4 — — 20.4 Miscellaneous 9.2 0.1 0.2 9.5 Total Customer Revenues $ 406.5 $ 449.1 $ 0.2 $ 855.8 Other Revenues 12.1 27.1 — 39.2 Total Operating Revenues $ 418.6 $ 476.2 $ 0.2 $ 895.0 (1) Customer revenue amounts exclude intersegment revenues. See Note 19, "Business Segment Information," for discussion of intersegment revenues. 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 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 19, "Business Segment Information," for discussion of intersegment revenues. Nine Months Ended September 30, 2018 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 1,540.3 $ 382.3 $ — $ 1,922.6 Commercial 516.2 374.2 — 890.4 Industrial 161.3 468.1 — 629.4 Off-system 63.6 — — 63.6 Miscellaneous 36.2 12.3 0.6 49.1 Total Customer Revenues $ 2,317.6 $ 1,236.9 $ 0.6 $ 3,555.1 Other Revenues 30.2 67.5 — 97.7 Total Operating Revenues $ 2,347.8 $ 1,304.4 $ 0.6 $ 3,652.8 (1) Customer revenue amounts exclude intersegment revenues. See Note 19, "Business Segment Information," for discussion of intersegment revenues. 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, 2019 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, 2018 $ 540.5 $ 349.1 Balance as of September 30, 2019 297.1 193.3 Increase (Decrease) $ (243.4 ) $ (155.8 )

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic EPS is computed by dividing net income 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 (See Note 5 "Equity"). The computation of diluted average common shares for the three months ended September 30, 2019 and the three and nine months ended September 30, 2018 is not presented since we had a net loss on the Condensed Statements of Consolidated Income (Loss) (unaudited) during the periods, and any incremental shares would have had an anti-dilutive impact on EPS. The computation of diluted average common shares for the nine months ended September 30, 2019 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, 2019
Equity [Abstract]
Equity	Equity Common Stock. As of September 30, 2019 , we had 600,000,000 shares of common stock authorized for issuance, of which 373,446,862 shares were outstanding. ATM Program and Forward Sale Agreements. On August 1, 2019, we amended four separate equity distribution agreements originally entered into on November 1, 2018, pursuant to which we may sell, from time to time, up to an aggregate value of $434.4 million of our common stock. The agreements expire on December 31, 2020. On December 6, 2018, 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 December 6, 2018 to December 10, 2018, 4,708,098 shares were borrowed from third parties and sold by the dealer at a weighted average price of $26.55 per share. We may settle this agreement in shares, cash, or net shares by December 6, 2019. Had we settled all the shares under the forward agreement at September 30, 2019 , we would have received approximately $123.3 million , based on a net price of $26.19 per share. On August 12, 2019, under the ATM program, we executed a separate forward agreement similar to that discussed above. From August 12, 2019 to September 13, 2019, 3,714,400 shares were borrowed from third parties and sold by the dealer at a weighted average price of $29.26 per share. We may settle this agreement in shares, cash, or net shares by December 31, 2019. Had we settled all the shares under the forward agreement at September 30, 2019 , we would have received approximately $107.6 million , based on a net price of $28.98 per share. As of September 30, 2019 , the ATM program (including impacts of the forward sale agreements discussed above) had $200.7 million of equity available for issuance. Preferred Stock . As of September 30, 2019 , 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 September 30, Nine Months Ended September 30, December 31, 2019 2018 2019 2018 2019 2018 (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 $ 28.88 $ 56.50 $ 28.88 $ 393.9 $ 393.9 6.500% Series B $ 25,000.00 20,000 $ 406.25 $ — $ 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 issued as a distribution with respect to the Series B Preferred Stock in order to enhance the voting rights of the Series B Preferred Stock to comply with the New York Stock Exchange’s minimum voting rights policy. 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.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2019
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, 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 Effective Columbia of Ohio IRP - 2019 (1) 18.2 199.6 1/18-12/18 February 28, 2019 Approved May 2019 Columbia of Ohio CEP - 2018 74.5 659.9 1/11-12/17 December 1, 2017 Approved December 2018 Columbia of Ohio CEP - 2019 15.0 121.7 1/18-12/18 February 28, 2019 Approved September 2019 NIPSCO - Gas TDSIC 9 (1)(2) (10.6 ) 54.4 1/18-6/18 August 28, 2018 Approved January 2019 NIPSCO - Gas TDSIC 10 (3) 1.6 12.4 7/18-4/19 June 25, 2019 Approved November 2019 NIPSCO - Gas FMCA 1 (4) 9.9 1.5 11/17-9/18 November 30, 2018 Approved April 2019 NIPSCO - Gas FMCA 2 (4) (3.5 ) 1.8 10/18-3/19 May 29, 2019 Approved September 25, 2019 October 2019 Columbia of Massachusetts GSEP - 2019 (5) 10.7 64.0 1/19-12/19 October 31, 2018 Approved May 2019 Columbia of Virginia SAVE - 2019 2.4 36.0 1/19-12/19 August 17, 2018 Approved January 2019 Columbia of Virginia SAVE - 2020 3.8 48.3 1/20-12/20 August 15, 2019 Order Expected Q4 2019 January 2020 Columbia of Kentucky AMRP - 2019 3.6 30.1 1/19-12/19 October 15, 2018 Approved January 2019 Columbia of Kentucky AMRP - 2020 4.2 40.4 1/20-12/20 October 15, 2019 Order Expected January 2020 Columbia of Maryland STRIDE - 2019 1.2 15.9 1/19-12/19 November 1, 2018 Approved January 2019 NIPSCO - Electric TDSIC - 5 (1) 15.9 58.8 6/18-11/18 January 29, 2019 Approved June 2019 NIPSCO - Electric TDSIC - 6 28.1 131.1 12/18-6/19 August 21, 2019 Order Expected Q4 2019 January 2020 NIPSCO - Electric FMCA - 11 (4) 0.9 22.4 9/18-2/19 April 17, 2019 Approved August 2019 NIPSCO - Electric FMCA - 12 (4) 1.6 4.7 3/19-8/19 October 18, 2019 Order Expected January 2020 February 2020 (1) Incremental revenue is net of amounts due back to customers as a result of the TCJA. (2) Incremental revenue is net of $5.2 million of adjustments in the TDSIC-9 settlement. (3) Incremental capital and revenue are net of amounts included in the step 2 base rate implementation. (4) Incremental revenue is inclusive of tracker eligible operations and maintenance expense. (5) Incremental capital investment anticipated to be lower than $64.0 million for 2019. 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 Effective NIPSCO - Gas (1) $ 138.1 $ 107.3 September 27, 2017 Approved October 2018 Columbia of Virginia (2) $ 14.2 $ 1.3 August 28, 2018 Approved February 2019 NIPSCO - Electric (3) $ 21.4 $ (45.0 ) October 31, 2018 Partial settlement filed First quarter of 2020 Columbia of Maryland $ 2.5 In Process May 22, 2019 Order Expected January 2020 (1) Rates will be implemented in three steps, with implementation of step 1 rates effective October 1, 2018. Step 2 rates were effective on March 1, 2019, and step 3 rates will be effective on January 1, 2020. The IURC’s order also dismissed NIPSCO from phase 2 of the IURC’s TCJA investigation. (2) Rates as originally filed were implemented in February 2019 on an interim basis, subject to refund. The final approved rates, which replaced interim rates, were implemented in July 2019. (3) An order on the partial settlement agreement, including the resolution of outstanding TCJA impacts to rates is currently pending before the IURC. The as-filed request and partial settlement agreement also includes $83.6 million and $85.3 million , respectively, of reductions to the fuel component of base rates related to a proposed change in service structure. Additional Regulatory Matters NIPSCO Electric. On March 29, 2018, WCE, which is currently owned by BP p.l.c ("BP") and BP Products North America, which operates the BP Refinery, filed a petition at the IURC asking that the combined operations of WCE and BP be treated as a single premise, and the WCE generation be dedicated primarily to BP Refinery operations beginning in May 2019 as WCE has self-certified as a qualifying facility at FERC. BP Refinery planned to continue to purchase electric service from NIPSCO at a reduced demand level beginning in May 2019; however, a settlement agreement was filed on November 2, 2018 agreeing that BP and WCE would not move forward with construction of a private transmission line to serve BP until conclusion of NIPSCO’s pending electric rate case. The IURC approved the settlement agreement as filed on February 20, 2019.

Risk Management Activities

Risk Management Activities	9 Months Ended
	Sep. 30, 2019
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, 2019 December 31, 2018 Risk Management Assets - Current (1) Interest rate risk programs $ — $ — Commodity price risk programs 1.0 1.1 Total $ 1.0 $ 1.1 Risk Management Assets - Noncurrent (2) Interest rate risk programs $ — $ 18.5 Commodity price risk programs 4.3 4.4 Total $ 4.3 $ 22.9 Risk Management Liabilities - Current (3) Interest rate risk programs $ 46.4 $ — Commodity price risk programs 10.7 5.0 Total $ 57.1 $ 5.0 Risk Management Liabilities - Noncurrent Interest rate risk programs $ 78.1 $ 9.5 Commodity price risk programs 46.9 37.2 Total $ 125.0 $ 46.7 (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). (3) Presented in "Other accruals" 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 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 to ten years and is limited to 20 percent of NIPSCO’s average annual GCA purchase volume. Gains and losses on these derivative contracts are deferred as regulatory liabilities or assets and are remitted to or collected from customers through NIPSCO’s quarterly GCA mechanism. These instruments are not designated as accounting hedges. Interest Rate Risk Management As of September 30, 2019 , we have 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 are 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, 2019 and December 31, 2018 . Our derivative instruments measured at fair value as of September 30, 2019 and December 31, 2018 do not contain any credit-risk-related contingent features.

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 : Recurring Fair Value Measurements (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of September 30, 2019 Assets Risk management assets $ — $ 5.3 $ — $ 5.3 Available-for-sale securities — 145.7 — 145.7 Total $ — $ 151.0 $ — $ 151.0 Liabilities Risk management liabilities $ — $ 182.1 $ — $ 182.1 Total $ — $ 182.1 $ — $ 182.1 Recurring Fair Value Measurements (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of December 31, 2018 Assets Risk management assets $ — $ 24.0 $ — $ 24.0 Available-for-sale securities — 138.3 — 138.3 Total $ — $ 162.3 $ — $ 162.3 Liabilities Risk management liabilities $ — $ 51.7 $ — $ 51.7 Total $ — $ 51.7 $ — $ 51.7 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, 2019 and December 31, 2018 , 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. We have entered into forward-starting interest rate swaps to hedge the interest rate risk on coupon payments of forecasted issuances of long-term debt. These derivatives are designated as cash flow hedges. Credit risk is considered in the fair value calculation of each agreement. 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. For additional information, see Note 7 , "Risk Management Activities." NIPSCO has entered into long-term forward natural gas purchase instruments that range from five to ten years 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 7 , “Risk Management Activities.” Available-for-sale securities are investments pledged as collateral for trust accounts related to our wholly-owned insurance company. Available-for-sale securities are included within “Other investments” in the Condensed Consolidated Balance Sheets (unaudited). 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. Total unrealized gains and losses from available-for-sale securities are included in other comprehensive income. The amortized cost, gross unrealized gains and losses and fair value of available-for-sale securities at September 30, 2019 and December 31, 2018 were: September 30, 2019 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities U.S. Treasury debt securities $ 31.1 $ 0.2 $ (0.1 ) $ 31.2 Corporate/Other debt securities 110.6 4.1 (0.2 ) 114.5 Total $ 141.7 $ 4.3 $ (0.3 ) $ 145.7 December 31, 2018 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities U.S. Treasury debt securities $ 23.6 $ 0.1 $ (0.1 ) $ 23.6 Corporate/Other debt securities 117.7 0.4 (3.4 ) 114.7 Total $ 141.3 $ 0.5 $ (3.5 ) $ 138.3 Realized gains and losses on available-for-sale securities were immaterial for the three and nine months ended September 30, 2019 and 2018 . The cost of maturities sold is based upon specific identification. At September 30, 2019 , approximately $6.8 million of U.S. Treasury debt securities and approximately $4.5 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 for the three and nine months ended September 30, 2019 and 2018 . Non-recurring Fair Value Measurements. There were no significant non-recurring fair value measurements recorded during the three and nine months ended September 30, 2019 . 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. For the three and nine months ended September 30, 2019 , 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 Amount as of Dec. 31, 2018 Estimated Fair Value as of Dec. 31, 2018 Long-term debt (including current portion) $ 7,864.7 $ 8,865.2 $ 7,155.4 $ 7,228.3

Transfers Of Financial Assets

Transfers Of Financial Assets	9 Months Ended
	Sep. 30, 2019
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 2020 and October 2020 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, 2019 , the maximum amount of debt that could be recognized related to our accounts receivable programs is $270.0 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, 2019 and December 31, 2018 : (in millions) September 30, 2019 December 31, 2018 Gross Receivables $ 375.1 $ 694.4 Less: Receivables not transferred 115.0 295.2 Net receivables transferred $ 260.1 $ 399.2 Short-term debt due to asset securitization $ 260.1 $ 399.2 For the nine months ended September 30, 2019 and 2018 , $139.1 million and $71.7 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 $0.4 million for the three months ended September 30, 2019 and 2018 , respectively, and $2.0 million and $1.9 million for the nine months ended September 30, 2019 and 2018, respectively. We remain responsible for collecting on the receivables securitized, and the receivables cannot be transferred to another party.

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The following presents our goodwill balance allocated by segment as of September 30, 2019 : (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Goodwill $ 1,690.7 $ — $ — $ 1,690.7 For our annual goodwill impairment analysis most recently performed as of May 1, 2019, we completed a qualitative "step 0" analysis for all reporting units other than our Columbia of Massachusetts reporting unit. In the step 0 analysis, we assessed various assumptions, events and circumstances that would have affected the estimated fair value of the applicable reporting units as compared to their baseline May 1, 2016 "step 1" fair value measurement. The results of this assessment indicated that it was not more likely than not that the fair values of these reporting units were less than their respective carrying values, accordingly, no "step 1" analysis was required. The results of our Columbia of Massachusetts reporting unit were negatively impacted by the Greater Lawrence Incident (see Note 16 , "Other Commitments and Contingencies"). As a result, we completed a quantitative "step 1" analysis for the May 1, 2019 goodwill analysis for this reporting unit. The step 1 analysis performed indicated that the fair value of the Columbia of Massachusetts reporting unit substantially exceeds its carrying value. As a result, no impairment charge was recorded as of the May 1, 2019 test date. This analysis incorporated the latest available cash flow projections reflecting the estimated ongoing impacts of the Greater Lawrence Incident on Columbia of Massachusetts' operations. We also incorporated other significant inputs to our fair value calculation (e.g. discount rate, market multiples) to reflect current market conditions. We will continue to monitor the impacts of the incident for events that could trigger a new impairment analysis including, but not limited to, unfavorable regulatory outcomes and regulator fines and penalties. As of September 30, 2019, goodwill at Columbia of Massachusetts totaled $204.8 million .

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our interim effective tax rates reflect the estimated annual effective tax rates for 2019 and 2018, adjusted for tax expense associated with certain discrete items. The effective tax rates for the three months ended September 30, 2019 and 2018 were 283.3% and 21.8% , respectively. The effective tax rates for the nine months ended September 30, 2019 and 2018 were 18.8% and 40.3% , respectively. These effective tax rates differ from the federal statutory tax rate of 21% primarily due to the effects of tax credits, state income taxes, the amortization of excess deferred federal income tax liabilities, as specified in the TCJA and in utility ratemaking proceedings, 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 increase in the three month effective tax rate of 261.5% in 2019 versus the same period in 2018 is primarily due to the relative impact of permanent differences on lower pre-tax loss. The decrease in the nine month effective tax rate of 21.5% in 2019 versus the same period in 2018 is primarily due to the relative impact of permanent differences on higher pre-tax book income. There were no material changes recorded in 2019 to our uncertain tax positions as of December 31, 2018 , however it is reasonably possible the total amount of our unrecognized tax benefits related to state tax positions will significantly change within the next 12 months. We cannot reasonably estimate the range of this potential change at this time.

Pension And Other Postretiremen

Pension And Other Postretirement Benefits	9 Months Ended
	Sep. 30, 2019
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. For most plans, cash contributions are remitted to grantor trusts. For the nine months ended September 30, 2019 , we contributed $2.1 million to our pension plans and $17.8 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, 2019 and 2018 : Pension Benefits Other Postretirement Benefits Three Months Ended September 30, (in millions) 2019 2018 2019 2018 Components of Net Periodic Benefit Cost (1) Service cost $ 7.3 $ 7.8 $ 1.3 $ 1.3 Interest cost 18.1 16.8 4.8 4.4 Expected return on assets (27.2 ) (35.4 ) (3.3 ) (3.7 ) Amortization of prior service credit — (0.1 ) (0.8 ) (1.0 ) Recognized actuarial loss 11.3 10.2 0.5 0.9 Settlement loss 1.9 8.3 — — Total Net Periodic Benefit Cost $ 11.4 $ 7.6 $ 2.5 $ 1.9 (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 (unaudited). Pension Benefits Other Postretirement Benefits Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Components of Net Periodic Benefit Cost (1) Service cost $ 21.9 $ 23.6 $ 3.9 $ 3.9 Interest cost 54.5 50.0 14.4 13.2 Expected return on assets (81.6 ) (107.9 ) (9.9 ) (11.1 ) Amortization of prior service credit — (0.3 ) (2.4 ) (3.0 ) Recognized actuarial loss 34.1 30.6 1.5 2.7 Settlement loss 1.9 11.8 — — Total Net Periodic Benefit Cost $ 30.8 $ 7.8 $ 7.5 $ 5.7 (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 (unaudited). As of August 31, 2019, two of our qualified pension plans met the requirement for settlement accounting. A settlement charge of $1.9 million was recorded during the third quarter of 2019. As a result of the settlement, these pension plans were remeasured. The remeasurements led to a decrease to the pension benefit obligation, net of plan assets, of $2.2 million , a net decrease to regulatory assets of $4.0 million , and a net credit to accumulated other comprehensive loss of $0.1 million . Net periodic pension benefit cost for 2019 decreased by $0.7 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 at the measurement date of August 31, 2019: August 31, 2019 Weighted-average Assumption to Determine Benefit Obligation Discount rate 2.80 % Weighted-average Assumptions to Determine Net Periodic Benefit Costs for the period ended Discount rate - service cost 4.49 % Discount rate - interest cost 3.84 % Expected return on assets 5.70 %

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2019
Long-term Debt, Current and Noncurrent [Abstract]
Long-term Debt	Long-Term Debt On April 1, 2019, NIPSCO repaid $41.0 million of 5.85% pollution control bonds at maturity. On August 12, 2019, we closed our placement of $750.0 million of 2.95% senior unsecured notes maturing in 2029 which resulted in approximately $742.4 million of net proceeds after deducting commissions and expenses.

Short-Term Borrowings

Short-Term Borrowings	9 Months Ended
	Sep. 30, 2019
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 borrowings. 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. On February 20, 2019, we extended the termination date of our revolving credit facility to February 20, 2024. At September 30, 2019 and December 31, 2018 , we had no outstanding borrowings under this facility. 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 $505.0 million and $978.0 million of commercial paper outstanding as of September 30, 2019 and December 31, 2018 , respectively. 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 $260.1 million in transfers as of September 30, 2019 and $399.2 million as of December 31, 2018 . Refer to Note 9 , "Transfers of Financial Assets," for additional information. On April 17, 2019 , we amended our existing term loan agreement with a syndicate of banks, with MUFG Bank Ltd. as the Administrative Agent, Sole Lead Arranger and Sole Bookrunner. The amendment increased the amount of our term loan from $600.0 million to $850.0 million and extended the maturity date to April 16, 2020 . 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 17, 2019 with an interest rate of LIBOR plus 60 basis points. Short-term borrowings were as follows: (in millions) September 30, December 31, Commercial paper weighted-average interest rate of 2.74% and 2.96% at September 30, 2019 and December 31, 2018, respectively $ 505.0 $ 978.0 Accounts receivable securitization facility borrowings 260.1 399.2 Term loan weighted-average interest rate of 2.65% and 3.07% at September 30, 2019 and December 31, 2018, respectively 850.0 600.0 Total Short-Term Borrowings $ 1,615.1 $ 1,977.2 Other than for the term loan 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.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases ASC 842 Adoption. In February 2016, the FASB issued ASU 2016-02, Leases (ASC 842). ASU 2016-02 introduces a lessee model that brings most leases onto the balance sheet. The standard requires that lessees recognize the following for all leases (with the exception of short-term leases, as that term is defined in the standard) at the lease commencement date: (1) a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and (2) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. In 2018, the FASB issued ASU 2018-01, Leases (ASC 842): Land Easement Practical Expedient for Transition to ASC 842, which allows us to not evaluate existing land easements under ASC 842, and ASU 2018-11, Leases (ASC 842): Targeted Improvements, which allows calendar year entities to initially apply ASC 842 prospectively from January 1, 2019. We adopted the provisions of ASC 842 beginning on January 1, 2019, using the transition method provided in ASU 2018-11, which was applied to all existing leases at that date. As such, results for reporting periods beginning after January 1, 2019 will be presented under ASC 842, while prior period amounts will continue to be reported in accordance with ASC 840. We elected a number of practical expedients, including the "practical expedient package" described in ASC 842-10-65-1 and the provisions of ASU 2018-01, which allows us to not evaluate existing land easements under ASC 842. Further, ASC 842 provides lessees the option of electing an accounting policy, by class of underlying asset, in which the lessee may choose not to separate nonlease components from lease components. We elected this practical expedient for our leases of fleet vehicles, IT assets and railcars. We elected to use a practical expedient that allows the use of hindsight in determining lease terms when evaluating leases that existed at the implementation date. We also elected the short-term lease recognition exemption, allowing us to not recognize ROU assets or lease liabilities for all leases that qualify. Adoption of the new standard resulted in the recording of additional lease liabilities and corresponding ROU assets of $57.0 million on our Condensed Consolidated Balance Sheets (unaudited) as of January 1, 2019. The standard had no material impact on our Condensed Statements of Consolidated Income (Loss) (unaudited) or our Condensed Statements of Consolidated Cash Flows (unaudited). Lease Descriptions. We are the lessee for substantially all of our leasing activity, which includes operating and finance leases for corporate and field offices, railcars, fleet vehicles and certain IT assets. Our corporate and field office leases have remaining lease terms between 1 and 25 years with options to renew the leases for up to 25 years . We lease railcars to transport coal to and from our electric generation facilities in Indiana. Our railcars are specifically identified in the lease agreements and have lease terms between 1 and 3 years with options to renew for 1 year . Our fleet vehicles include trucks, trailers and equipment that have been customized specifically for use in the utility industry. We lease fleet vehicles on 1 year terms, after which we have the option to extend on a month-to-month basis or terminate with written notice. ROU assets and liabilities on our Condensed Consolidated Balance Sheets (unaudited) do not include obligations for possible fleet vehicle lease renewals beyond the initial lease term. While we have the ability to renew these leases beyond the initial term, we are not reasonably certain to do so. We lease the majority of our IT assets under 4 year lease terms. Ownership of leased IT assets is transferred to us at the end of the lease term. We have not provided material residual value guarantees for our leases, nor do our leases contain material restrictions or covenants. Lease contracts containing renewal and termination options are mostly exercisable at our sole discretion. Certain of our real estate and railcar leases include renewal periods in the measurement of the lease obligation if we have deemed the renewals reasonably certain to be exercised. With respect to service contracts involving the use of assets, if we have the right to direct the use of the asset and obtain substantially all economic benefits from the use of an asset, we account for the service contract as a lease. Unless specifically provided to us by the lessor, we utilize NiSource's collateralized incremental borrowing rate commensurate to the lease term as the discount rate for all of our leases. Lease costs for the three and nine months ended September 30, 2019 are presented in the table below. These costs include both amounts recognized in expense and amounts capitalized as part of the cost of another asset. Income statement presentation for these costs (when ultimately recognized on the income statement) is also included: Three Months Ended Nine Months Ended (in millions) Income Statement Classification 2019 2019 Finance lease cost Amortization of right-of-use assets Depreciation and amortization $ 3.6 $ 11.3 Interest on lease liabilities Interest expense, net 3.1 8.5 Total finance lease cost 6.7 19.8 Operating lease cost Operation and maintenance 5.3 12.3 Short-term lease cost Operation and maintenance 0.1 0.9 Total lease cost $ 12.1 $ 33.0 Our right-of-use assets and liabilities are presented in the following lines on the Condensed Consolidated Balance Sheets (unaudited): (in millions) Balance Sheet Classification September 30, 2019 Assets Finance leases Net Property, Plant and Equipment $ 176.5 Operating leases Deferred charges and other 60.9 Total leased assets 237.4 Liabilities Current Finance leases Current portion of long-term debt 10.7 Operating leases Other accruals 10.5 Noncurrent Finance leases Long-term debt, excluding amounts due within one year 187.2 Operating leases Other noncurrent liabilities 50.5 Total lease liabilities $ 258.9 Other pertinent information related to leases was as follows: Nine Months Ended September 30, (in millions) 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows used for finance leases $ 8.4 Operating cash flows used for operating leases 11.8 Financing cash flows used for finance leases 7.7 Right-of-use assets obtained in exchange for lease obligations Finance leases 11.0 Operating leases $ 3.7 September 30, 2019 Weighted-average remaining lease term (years) Finance leases 15.5 Operating leases 9.7 Weighted-average discount rate Finance leases 6.0 % Operating leases 4.4 % Maturities of our lease liabilities presented on a rolling 12-month basis were as follows: As of September 30, 2019, (in millions) Total Finance Leases Operating Leases Year 1 $ 37.7 $ 24.5 $ 13.2 Year 2 33.9 24.6 9.3 Year 3 32.8 24.6 8.2 Year 4 29.3 21.6 7.7 Year 5 27.6 20.6 7.0 Thereafter 247.8 214.8 33.0 Total lease payments 409.1 330.7 78.4 Less: Imputed interest (121.6 ) (107.0 ) (14.6 ) Less: Leases not yet commenced (1) (28.6 ) (25.8 ) (2.8 ) Total 258.9 197.9 61.0 Reported as of September 30, 2019 Short-term lease liabilities 21.2 10.7 10.5 Long-term lease liabilities 237.7 187.2 50.5 Total lease liabilities $ 258.9 $ 197.9 $ 61.0 (1) Expected payments include obligations for leases not yet commenced of approximately $28.6 million for interconnection facilities and corporate and field offices. The facilities will have lease terms between 8 years and 20 years , with estimated commencements in the fourth quarter of 2019 and in the third quarter of 2020. Disclosures Related to Periods Prior to Adoption of ASC 842. As of December 31, 2018 , total contractual obligations for capital and operating leases were as follows: As of December 31, 2018, (in millions) Total Capital Leases (1) Operating Leases (2) 2019 $ 34.0 $ 23.0 $ 11.0 2020 29.8 22.5 7.3 2021 28.7 22.6 6.1 2022 26.3 22.1 4.2 2023 22.6 19.8 2.8 Thereafter 226.9 212.4 14.5 Total lease payments $ 368.3 $ 322.4 $ 45.9 (1) Capital lease payments shown above are inclusive of interest totaling $114.6 million . (2) Operating lease balances do not include obligations for possible fleet vehicle lease renewals beyond the initial lease term. While we have the ability to renew these leases beyond the initial term, we are not reasonably certain to do so. Expected payments are $26.7 million in 2019, $22.4 million in 2020, $16.6 million in 2021, $12.3 million in 2022, $9.3 million in 2023 and $8.8 million thereafter.

Other Commitments And Contingen

Other Commitments And Contingencies	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018, we had issued stand-by letters of credit of $10.2 million . 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 service 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. We are subject to inquiries and investigations by federal and state government authorities and regulatory agencies regarding the Greater Lawrence Incident. The NTSB has concluded its investigation. The U.S Attorney’s office, the SEC, and the Massachusetts DPU have pending investigations related to the Greater Lawrence Incident, as described below. We are also subject to inquiries by the Massachusetts Attorney General’s Office. We are cooperating with all inquiries and investigations. The outcomes and impacts of the current investigations and any future investigations that may be commenced related to such inquiries are uncertain at this time. NTSB Investigation. The NTSB investigated the Greater Lawrence Incident as described below. The parties to the investigation included the PHMSA, the Massachusetts DPU, Columbia of Massachusetts, and the Massachusetts State Police. We cooperated with the NTSB and provided information to assist in its investigation into relevant facts related to the event, the probable cause, and its development of safety recommendations. According to the preliminary public report that the NTSB issued on October 11, 2018, an over-pressurization of a low-pressure gas distribution system occurred that was related to work being done on behalf of Columbia of Massachusetts on a pipeline replacement project in Lawrence. According to the report, sensing lines detected a drop in pressure in a portion of mainline that was being abandoned, causing a regulator to open up and increase pressure in the system to a level that exceeded the maximum allowable operating pressure of the distribution system. On November 14, 2018, the NTSB issued an urgent safety recommendation report regarding natural gas distribution system project development and review. In its report, the NTSB identified certain factors that it believes contributed to the Greater Lawrence Incident and made safety recommendations. The NTSB recommended that the Commonwealth of Massachusetts eliminate the professional engineer licensure exemption for public utility work and require a professional engineer’s seal on public utility engineering drawings, which is now law in Massachusetts. The NTSB also made recommendations to us related to engineering plan and constructability review processes, records and documentation, management of change processes, and control procedures during modifications to gas mains. We implemented these recommendations. As of September 24, 2019, each of these recommendations has been closed by the NTSB based on acceptable action. Since the Greater Lawrence Incident, we have identified and proceeded with additional steps to enhance system safety and reliability and to safeguard against future over-pressurization events. Some of these measures have already been completed and others are in process. These Company-wide safety measures include enhanced measures as called for in the NTSB’s recommendations. For example, we have committed to a program to install over-pressurization protection devices on all of our low-pressure systems, which is described in “- D. Other Matters.” On September 24, 2019, the NTSB held a public board meeting regarding the probable cause of the Greater Lawrence Incident. The NTSB issued an abstract of its final report following the meeting, and its final report on October 24, 2019. The NTSB stated that it had determined that the probable cause of the over-pressurization of the natural gas distribution system and the resulting fires and explosions was Columbia of Massachusetts’ weak engineering management that did not adequately plan, review, sequence, and oversee the construction project that led to the abandonment of a cast iron main without first relocating regulator sensing lines to the new polyethylene main. The NTSB also stated that contributing to the incident was a low-pressure natural gas distribution system designed and operated without adequate overpressure protection. The NTSB issued its findings in connection with its investigation of the incident and new safety recommendations to PHMSA, certain other states, the Commonwealth of Massachusetts Executive Office of Public Safety and Security, and the Company. The one new safety recommendation that was directed to the Company requires the Company to review its protocols and training for responding to large-scale emergency events. Massachusetts Regulatory Matters. Under Massachusetts law, the 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 million per related series of violations. Further, as a result of the declaration of emergency by the Governor, the DPU is authorized to investigate potential violations of the DPU's operational directives during the restoration efforts and assess penalties of up to $1 million per violation. Pursuant to these authorities, the DPU is investigating the Greater Lawrence Incident. Columbia of Massachusetts will likely be subject to potential compliance actions related to the Greater Lawrence Incident and the restoration work following the incident, the timing and outcomes of which are uncertain at this time. After the Greater Lawrence Incident, the Massachusetts DPU retained an independent evaluator to conduct a statewide examination of the safety of the natural gas distribution system and the operational and maintenance functions of natural gas companies in the Commonwealth of Massachusetts. Through authority granted by the Massachusetts Governor under the state of emergency, the Chair of the Massachusetts DPU has directed all natural gas distribution companies operating in the Commonwealth to fund the statewide examination. The statewide examination is underway and we have responded to the evaluator’s information requests. The Phase I report, which was issued on May 15, 2019, included a program level assessment and evaluation of natural gas distribution companies. The Phase I report's conclusions were statewide and contained no specific conclusions about Columbia of Massachusetts. The evaluation remains in Phase II, which is focused on field assessments of each individual gas company and is expected to conclude later this year. On November 30, 2018, Columbia of Massachusetts entered into a consent order with the Massachusetts DPU in connection with a notice of probable violation issued in March 2018, stemming from a 2016 report. The Division found that Columbia of Massachusetts violated certain pipeline safety regulations related to pressure limiting and regulating stations in Taunton, Massachusetts. As part of the consent order, Columbia of Massachusetts was fined $75,000 and entered into a compliance agreement under which it agreed to take several actions related to its pressure regulator stations within various timeframes, including the adoption of a Pipeline Safety Management System ("SMS"), the American Petroleum Institute’s (API) Recommended Practice 1173. Columbia of Massachusetts is complying with the order. On December 17, 2018, the Massachusetts DPU issued an order requiring Columbia of Massachusetts to enter into an agreement with a Massachusetts-based engineering firm to monitor Columbia of Massachusetts’ remaining restoration and recovery work in Lawrence, Andover and North Andover, Massachusetts. The order requires Columbia of Massachusetts to take measures to ensure that adequate heat and hot water and gas appliances are provided to all affected properties, repave all affected streets, roadways, sidewalks and other areas in accordance with applicable DPU standards and precedents, consult with the affected communities and discuss plans for restoring affected hard or soft surfaces, and replace all gas boilers and furnaces and other gas-fired equipment at affected residences. Under the order, all restoration work beginning in 2019 was required to be completed no later than October 31, 2019, unless an earlier or later date is agreed to with any of the affected communities. We previously agreed to complete the gas appliance replacement work by September 15, 2019, and completed the work ahead of schedule as announced on August 15, 2019. We reached an agreement with the affected communities with regard to the timing and scope of hard and soft surface repairs, which is discussed in "Private Actions" below. On June 11, 2019, the Massachusetts DPU issued an order requiring Columbia of Massachusetts to comply with the terms of the agreement reached with the affected communities for the restoration of hard and soft surfaces. Also, under both the December 17, 2018 and June 11, 2019 orders, Columbia of Massachusetts is required to maintain quantitative measures, which must be verified by officials of the affected communities, to track its progress in completing all of the remaining work. Estimates for the cost of this work are included in the estimated ranges of loss noted below, which is discussed in “- D. Other Matters - Greater Lawrence Incident Restoration" and " - Greater Lawrence Pipeline Replacement” below. Our failure to adhere to any of the requirements in the order may result in penalties of up to $1 million per violation. In the third quarter of 2019, the Massachusetts DPU initiated several new investigations into Columbia of Massachusetts related to the restoration and other work following the Greater Lawrence Incident, as described below. Under Massachusetts law, the Massachusetts DPU is authorized to conduct investigations and assess fines and penalties as described above. The matters described below are pursuant to such authorization and are subject to the assessment of fines and penalties. In August 2019, the Massachusetts DPU initiated an investigation regarding pressure monitoring and potential violations of pipeline safety regulations in connection with the installation of a slam shut device and the operating procedures used to install such devices. The DPU also initiated an investigation regarding instances of possible violations of internal guidelines and state and/or federal pipeline safety regulations in connection with Columbia of Massachusetts’ project after the Greater Lawrence Incident to validate regulator station drawings and verify control line location and installation. In September 2019, the Massachusetts DPU initiated an investigation into potential violations of state and/or federal pipeline safety regulations in connection with abandoned service lines. The Chair of the Massachusetts DPU issued an emergency order directing Columbia of Massachusetts to take several specific actions to address concerns related to service lines abandoned during the restoration work following the Greater Lawrence Incident and to furnish certain information and periodic reports to the DPU. Estimates for the cost of this work are included in the estimated ranges of loss noted below, which is discussed in “- D. Other Matters - Greater Lawrence Incident Restoration" below. In addition, the Massachusetts DPU issued a Hearing Officer’s Memorandum directing Columbia of Massachusetts to file a detailed report concerning its emergency response to the Greater Lawrence Incident and subsequent restoration of service. On September 27, 2019, the City of Lawrence inadvertently closed a gas valve that had been incorrectly marked as a water valve, which severed a new pipeline main that Columbia of Massachusetts had installed during the restoration work following the Greater Lawrence Incident, resulting in the release of gas into sewer lines, other underground conduits and homes in the area. Approximately 150 homes and businesses were evacuated and electric power was turned off by the power company as a safety precaution to approximately 1,400 customers. The Massachusetts DPU is investigating whether, during the restoration efforts following the Greater Lawrence Incident, Columbia Gas failed to follow required procedures for the abandonment of valve boxes. On October 1, 2019, the Massachusetts DPU issued four orders to Columbia of Massachusetts in connection with the service lines abandoned during the Greater Lawrence Incident restoration, which require: (1) the submission of a detailed work plan to the DPU, (2) the completion of quality control work on certain abandoned services, (3) the payment for a third-party independent audit, to be contracted through the DPU, of all gas pipeline work completed as part of the incident restoration effort, and (4) prompt and full response to any requests for information by the third-party auditor. The audit will evaluate compliance with Massachusetts and federal law, as well as any other operational or safety risks that may be posed by the pipeline work. The audit will investigate Columbia of Massachusetts' operations in the Lawrence Division and other service territories as appropriate, either independently or as part of the statewide gas safety assessment already underway. Estimates for the cost of this work are included in the estimated ranges of loss noted below, which is discussed in “- D. Other Matters - Greater Lawrence Incident Restoration" below. Also in October 2019, the Massachusetts DPU issued three additional orders requiring: (1) daily leak surveillance and reporting in areas where abandoned services are located, (2) completion by November 15, 2019 of the work plan previously submitted describing how Columbia of Massachusetts will address the estimated 2,200 locations at which an inside meter set was moved outside the property as part of the abandoned service work completed during the Greater Lawrence Incident restoration, and (3) submission of a report by December 2, 2019 showing any patterns, trends or correlations among the noncompliant work related to the abandonment of service lines, gate boxes and curb boxes during the incident restoration. On October 3, 2019, the Massachusetts DPU notified Columbia of Massachusetts that, absent DPU approval, it is currently allowed to perform only emergency work on its gas distribution system throughout its service territories in Massachusetts. The restrictions do not apply to Columbia of Massachusetts’ ongoing work to address the previously identified issues with abandoned service lines and valve boxes in the Greater Lawrence, Massachusetts area. Columbia of Massachusetts is subject to daily monitoring by the DPU on any work that Columbia of Massachusetts conducts in Massachusetts. Such restrictions on work remain in place until modified by the DPU. On October 25, 2019, the Massachusetts DPU issued two orders opening public investigations into Columbia of Massachusetts. The Massachusetts DPU opened the first proceeding under its authority to determine compliance with federal and state pipeline safety laws and regulations, and will 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 proceeding under its authority to determine whether a gas distribution company has violated established standards regarding acceptable performance for emergency preparedness and restoration of service, and will investigate efforts by Columbia of Massachusetts to prepare for and restore service following the Greater Lawrence Incident. Separate penalties are applicable under each exercise of authority. Columbia of Massachusetts is cooperating with the investigations set forth above, the outcomes of which are uncertain at this time. Massachusetts Legislative Matters. In December 2018, the President of Columbia of Massachusetts testified before a joint state legislative committee on telecommunications, utilities and energy with other industry officials about gas system safety in Massachusetts and regulatory oversight. Increased scrutiny related to these matters, including additional legislative oversight hearings and new legislative proposals, is expected to continue during the current two-year legislative session. On December 31, 2018, the Massachusetts Governor signed into law legislation requiring a certified professional engineer to review and approve gas pipeline work that could pose a “material risk” to public safety, consistent with the NTSB’s recommendation. The Massachusetts DPU has issued interim guidelines and the existing moratorium has been lifted. The DPU issued an Order Opening Inquiry (Notice of Inquiry) on March 18, 2019, and Columbia of Massachusetts has submitted comments. Legislative hearings in Massachusetts related to proposed legislation on natural gas matters are expected to take place during the fourth quarter of 2019. In addition, the Joint Committee on Telecommunications, Utilities and Energy is expected to conduct a hearing on natural gas safety in November 2019. U.S. Department of Justice Investigation. The Company and Columbia of Massachusetts are subject to a criminal investigation related to the Greater Lawrence Incident that is being conducted under the supervision of the U.S. Attorney's Office for the District of Massachusetts. The initial grand jury subpoenas were served on the Company and Columbia of Massachusetts on September 24, 2018. The Company and Columbia of Massachusetts are cooperating with the investigation. We are unable to estimate the amount (or range of amounts) of reasonably possible losses associated with any civil or criminal penalties that could be imposed on the Company or Columbia of Massachusetts as a result of this investigation. U.S. Congressional Activity. In November 2018, executives of the Company and Columbia of Massachusetts testified at a U.S. Senate hearing regarding the Greater Lawrence Incident and natural gas pipeline safety. On September 30, 2019, the U.S. Pipeline Safety Act expired. There is no effect on PHMSA's authority. Action on past re-authorization bills has extended past the expiration date. 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). Legislative proposals are currently in various stages of committee development and the timing of further action is uncertain. Certain legislative proposals, if enacted into law, may increase costs for natural gas industry companies, including the Company and Columbia of Massachusetts. SEC Investigation. On February 11, 2019, the SEC notified the Company that it is conducting an investigation of the Company related to disclosures made prior to the Greater Lawrence Incident. We are cooperating with the investigation. 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 proposed settlement is subject to final court approval, and a hearing is scheduled for February 27, 2020. Many residents and business owners have submitted individual damage claims to Columbia of Massachusetts. We also have received notice from three parties indicating an intent to assert wrongful death claims. In Massachusetts, punitive damages are available in a wrongful death action upon proof of gross negligence or willful or reckless conduct causing the death. 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 except as set forth below. We are discussing potential settlements with plaintiffs asserting certain bodily injury and wrongful death claims. On April 25, 2019, we entered into a settlement agreement with certain of these plaintiffs involving bodily injury claims, subject to certain conditions, including court approval. On July 3, 2019, we entered into a settlement with one of the parties that indicated an intent to assert a wrongful death claim. On September 25, 2019, we entered into another settlement with a party that indicated an intent to assert a wrongful death claim. On May 7, 2019, Columbia of Massachusetts and the municipalities of Lawrence, Andover and North Andover jointly announced that they reached a settlement for expenses incurred by the municipalities in connection with the Greater Lawrence Incident, and for compensating the municipalities to repave affected streets, roadways and sidewalks. Financial Impact. We estimate that total costs related to third-party claims resulting from the incident will range from $995 million to $1,020 million , depending on the final outcome of ongoing reviews and the number, nature, and value of third-party claims. These costs include, but are not limited to, personal injury and property damage claims, damage to infrastructure, and mutual aid payments to other utilities assisting with the restoration effort. These costs related to third-party claims do not include costs of certain third-party claims that we are not able to estimate, nor do they include non-claims related expenses resulting from the incident and the estimated capital cost of the pipeline replacement, which are set forth in " - D. Other Matters - Greater Lawrence Incident Restoration" and "- Greater Lawrence Incident Pipeline Replacement," respectively, below. 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, including additional information regarding ongoing investigations, management’s estimates and assumptions regarding the financial impact of the Greater Lawrence Incident may change. The increase in estimated total costs related to third-party claims from those disclosed in our Form 10-K for the year ended December 31, 2018 resulted primarily from receiving additional information regarding legal claims and the required scope of the restoration work inside the affected homes. It is not possible at this time to reasonably estimate the total amount of any expenses associated with government investigations and fines, penalties or settlements with certain governmental authorities, including the Massachusetts DPU and other regulators, that we may incur in connection with the Greater Lawrence Incident. Therefore, the foregoing amounts do not include estimates of the total amount that we may incur for any such fines, penalties or settlements. The aggregate amount of third-party liability insurance coverage available for losses arising from the Greater Lawrence Incident is $800 million . Total expenses related to the incident have exceeded the total amount of insurance coverage available under our policies. While a substantial amount of expenses related to the Greater Lawrence Incident has already been recovered from insurance carriers, a few insurers providing liability insurance to the Company or Columbia of Massachusetts continue to review our claim under the terms and conditions of the respective insurance policies. We are not able to estimate the amount of expenses that will not be covered by insurance, but these amounts are material to our financial statements. Certain types of damages, expenses or claimed costs, such as fines or penalties, may be excluded under the 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. In addition, we are party to certain other claims and legal proceedings arising in the ordinary course of business, none of which is deemed to be individually material at this time. Due to the inherent uncertainty of litigation, there can be no assurance that the resolution of any particular claim or proceeding related to the Greater Lawrence Incident or otherwise would not have a material adverse effect on our results of operations, financial position or liquidity. If one or more of such 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, 2019 and December 31, 2018 , we had recorded a liability of $107.5 million and $101.2 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. See section 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 increase methane leak detection, require emission reductions or impose additional requirements for natural gas facilities could restrict GHG emissions and impose additional costs. We carefully monitor all GHG reduction proposals and regulations. CPP and ACE Rules. On July 8, 2019, the EPA published the final ACE rule and repealed the CPP. The ACE rule 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 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 wa

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2019
Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Income (Loss) The following tables display the components of Accumulated Other Comprehensive Income (Loss): 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. Three Months Ended September 30, 2018 (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, 2018 $ (2.2 ) $ (1.7 ) $ (17.0 ) $ (20.9 ) Other comprehensive income before reclassifications — 21.6 1.0 22.6 Amounts reclassified from accumulated other comprehensive income 0.1 0.9 (0.2 ) 0.8 Net current-period other comprehensive income 0.1 22.5 0.8 23.4 Balance as of September 30, 2018 $ (2.1 ) $ 20.8 $ (16.2 ) $ 2.5 (1) All amounts are net of tax. Amounts in parentheses indicate debits. Nine Months Ended September 30, 2018 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated Other Comprehensive Income (Loss) (1 ) Balance as of January 1, 2018 $ 0.2 $ (29.4 ) $ (14.2 ) $ (43.4 ) Other comprehensive income (loss) before reclassifications (2.5 ) 70.8 1.0 69.3 Amounts reclassified from accumulated other comprehensive income (loss) 0.2 (14.3 ) 0.2 (13.9 ) Net current-period other comprehensive income (loss) (2.3 ) 56.5 1.2 55.4 Reclassification due to adoption of ASU 2018-02 — (6.3 ) (3.2 ) (9.5 ) Balance as of September 30, 2018 $ (2.1 ) $ 20.8 $ (16.2 ) $ 2.5 (1) All amounts are net of tax. Amounts in parentheses indicate debits.

Other, Net

Other, Net	9 Months Ended
	Sep. 30, 2019
Other, Net [Abstract]
Other, Net	Other, Net Three Months Ended Nine Months Ended (in millions) 2019 2018 2019 2018 Interest income $ 2.1 $ 1.4 $ 5.4 $ 4.2 AFUDC equity 2.9 5.0 7.1 12.6 Charitable contributions (1.1 ) (11.1 ) (4.0 ) (13.9 ) Pension and other postretirement non-service cost (2.8 ) 2.4 (8.7 ) 14.7 Interest rate swap settlement gain — — — 21.2 Miscellaneous 0.2 0.6 0.5 3.6 Total Other, net $ 1.3 $ (1.7 ) $ 0.3 $ 42.4

Business Segment Information

Business Segment Information	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Business Segment Information	Business Segment Information At September 30, 2019 , 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 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) 2019 2018 2019 2018 Operating Revenues Gas Distribution Operations Unaffiliated $ 463.6 $ 418.6 $ 2,506.2 $ 2,347.8 Intersegment 3.3 3.3 9.9 9.8 Total 466.9 421.9 2,516.1 2,357.6 Electric Operations Unaffiliated 467.7 476.2 1,304.9 1,304.4 Intersegment 0.2 0.2 0.6 0.6 Total 467.9 476.4 1,305.5 1,305.0 Corporate and Other Unaffiliated 0.2 0.2 0.6 0.6 Intersegment 116.9 116.4 342.2 346.6 Total 117.1 116.6 342.8 347.2 Eliminations (120.4 ) (119.9 ) (352.7 ) (357.0 ) Consolidated Operating Revenues $ 931.5 $ 895.0 $ 3,811.7 $ 3,652.8 Operating Income (Loss) Gas Distribution Operations $ (48.6 ) $ (455.2 ) $ 605.8 $ (94.4 ) Electric Operations 140.7 134.9 321.4 300.4 Corporate and Other (1.1 ) 4.4 1.5 (2.9 ) Consolidated Operating Income (Loss) $ 91.0 $ (315.9 ) $ 928.7 $ 203.1

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Tables)	9 Months Ended
	Sep. 30, 2019
New Accounting Pronouncements and Changes in Accounting Principles [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 2019-04, Codification Improvements to Topic 326, Financial Instruments-Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments The pronouncement clarifies and improves certain areas of guidance related to the recently issued standards on credit losses, hedging, and recognition and measurement. Topics 1, 2, and 5 of this update amends ASU 2016-13 as it relates to accrued interest, transfers between investment classifications, expected recoveries and reinsurance recoverables. Topic 3 improves guidance related to fair value hedges. Topic 4 of this update relates to codification improvements to ASU 2016-01. Annual periods beginning after December 15, 2019, including interim periods therein. Early adoption is permitted. We maintain investments in U.S. Treasury, corporate and mortgage-backed debt securities, which are pledged as collateral for trust accounts related to our wholly-owned insurance company. These debt securities are classified as available for sale ("AFS"). We are working with our external investment manager to enhance our current impairment model for AFS debt securities to comply with the standard. Upon adoption of ASC 326, we will recognize impairment for AFS debt securities by implementing an allowance approach instead of an 'other than temporary' impairment model. In addition, we have recorded balances for trade receivables that also fall within the scope of the standard. Based on shared risk characteristics, we segregated our trade receivables into 'residential customer receivables' and 'non-residential customer receivables'. We intend to apply separate models to calculate reserves for uncollectible receivables. While we continue to assess and enhance our processes of recording reserves for uncollectible receivables to comply with the current expected credit loss model, we do not expect any significant modifications to our current policy of calculating uncollectible reserves for our 'residential customer receivables' balances. ASC 326 also prescribes additional presentation and disclosure requirements. We are currently reviewing the impact of these requirements on our disclosures related to credit in our Notes to Condensed Consolidated Financial Statements (unaudited). We are unable to reasonably estimate the quantitative impact of adoption on our Condensed Consolidated Financial Statements (unaudited). We expect to adopt this ASU on its effective date. ASU 2016-13, Financial Instruments-Credit Losses (Topic 326) The pronouncement changes the impairment model for most financial assets, replacing the current "incurred loss" model. ASU 2016-13 will require the use of an "expected loss" model for instruments measured at amortized cost. It will also require entities to record allowances for available-for-sale securities rather than impair the carrying amount of the securities. Subsequent improvements to the estimated credit losses of available-for-sale securities will be recognized immediately in earnings instead of over time as they are under historic guidance. 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 The 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 are currently evaluating the effects of this pronouncement on our Notes to Condensed Consolidated Financial Statements (unaudited). We expect to adopt this ASU on its effective date.
Schedule of Prospective Adoption of New Accounting Pronouncements	Recently Adopted Accounting Pronouncements Standard Adoption ASU 2019-01, Leases (Topic 842): Codification Improvements See Note 15, "Leases," for our discussion of the effects of implementing these standards. ASU 2018-11, Leases (Topic 842): Targeted Improvements ASU 2018-01, Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842 ASU 2016-02, Leases (Topic 842)

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and September 30, 2018: 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 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 19 , "Business Segment Information," for discussion of intersegment revenues. Three Months Ended September 30, 2018 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 257.0 $ 154.7 $ — $ 411.7 Commercial 80.9 140.7 — 221.6 Industrial 39.0 153.6 — 192.6 Off-system 20.4 — — 20.4 Miscellaneous 9.2 0.1 0.2 9.5 Total Customer Revenues $ 406.5 $ 449.1 $ 0.2 $ 855.8 Other Revenues 12.1 27.1 — 39.2 Total Operating Revenues $ 418.6 $ 476.2 $ 0.2 $ 895.0 (1) Customer revenue amounts exclude intersegment revenues. See Note 19, "Business Segment Information," for discussion of intersegment revenues. 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 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 19, "Business Segment Information," for discussion of intersegment revenues. Nine Months Ended September 30, 2018 (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Customer Revenues (1) Residential $ 1,540.3 $ 382.3 $ — $ 1,922.6 Commercial 516.2 374.2 — 890.4 Industrial 161.3 468.1 — 629.4 Off-system 63.6 — — 63.6 Miscellaneous 36.2 12.3 0.6 49.1 Total Customer Revenues $ 2,317.6 $ 1,236.9 $ 0.6 $ 3,555.1 Other Revenues 30.2 67.5 — 97.7 Total Operating Revenues $ 2,347.8 $ 1,304.4 $ 0.6 $ 3,652.8 (1) Customer revenue amounts exclude intersegment revenues. See Note 19, "Business Segment Information," for discussion of intersegment revenues.
Customer Accounts Receivable	The opening and closing balances of customer receivables for the nine months ended September 30, 2019 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, 2018 $ 540.5 $ 349.1 Balance as of September 30, 2019 297.1 193.3 Increase (Decrease) $ (243.4 ) $ (155.8 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Computation Of Diluted Average Common Shares	The computation of diluted average common shares for the nine months ended September 30, 2019 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, 2019
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 September 30, Nine Months Ended September 30, December 31, 2019 2018 2019 2018 2019 2018 (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 $ 28.88 $ 56.50 $ 28.88 $ 393.9 $ 393.9 6.500% Series B $ 25,000.00 20,000 $ 406.25 $ — $ 1,674.65 $ — $ 486.1 $ 486.1

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2019
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 Effective Columbia of Ohio IRP - 2019 (1) 18.2 199.6 1/18-12/18 February 28, 2019 Approved May 2019 Columbia of Ohio CEP - 2018 74.5 659.9 1/11-12/17 December 1, 2017 Approved December 2018 Columbia of Ohio CEP - 2019 15.0 121.7 1/18-12/18 February 28, 2019 Approved September 2019 NIPSCO - Gas TDSIC 9 (1)(2) (10.6 ) 54.4 1/18-6/18 August 28, 2018 Approved January 2019 NIPSCO - Gas TDSIC 10 (3) 1.6 12.4 7/18-4/19 June 25, 2019 Approved November 2019 NIPSCO - Gas FMCA 1 (4) 9.9 1.5 11/17-9/18 November 30, 2018 Approved April 2019 NIPSCO - Gas FMCA 2 (4) (3.5 ) 1.8 10/18-3/19 May 29, 2019 Approved September 25, 2019 October 2019 Columbia of Massachusetts GSEP - 2019 (5) 10.7 64.0 1/19-12/19 October 31, 2018 Approved May 2019 Columbia of Virginia SAVE - 2019 2.4 36.0 1/19-12/19 August 17, 2018 Approved January 2019 Columbia of Virginia SAVE - 2020 3.8 48.3 1/20-12/20 August 15, 2019 Order Expected Q4 2019 January 2020 Columbia of Kentucky AMRP - 2019 3.6 30.1 1/19-12/19 October 15, 2018 Approved January 2019 Columbia of Kentucky AMRP - 2020 4.2 40.4 1/20-12/20 October 15, 2019 Order Expected January 2020 Columbia of Maryland STRIDE - 2019 1.2 15.9 1/19-12/19 November 1, 2018 Approved January 2019 NIPSCO - Electric TDSIC - 5 (1) 15.9 58.8 6/18-11/18 January 29, 2019 Approved June 2019 NIPSCO - Electric TDSIC - 6 28.1 131.1 12/18-6/19 August 21, 2019 Order Expected Q4 2019 January 2020 NIPSCO - Electric FMCA - 11 (4) 0.9 22.4 9/18-2/19 April 17, 2019 Approved August 2019 NIPSCO - Electric FMCA - 12 (4) 1.6 4.7 3/19-8/19 October 18, 2019 Order Expected January 2020 February 2020 (1) Incremental revenue is net of amounts due back to customers as a result of the TCJA. (2) Incremental revenue is net of $5.2 million of adjustments in the TDSIC-9 settlement. (3) Incremental capital and revenue are net of amounts included in the step 2 base rate implementation. (4) Incremental revenue is inclusive of tracker eligible operations and maintenance expense. (5) Incremental capital investment anticipated to be lower than $64.0 million for 2019.
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 Effective NIPSCO - Gas (1) $ 138.1 $ 107.3 September 27, 2017 Approved October 2018 Columbia of Virginia (2) $ 14.2 $ 1.3 August 28, 2018 Approved February 2019 NIPSCO - Electric (3) $ 21.4 $ (45.0 ) October 31, 2018 Partial settlement filed First quarter of 2020 Columbia of Maryland $ 2.5 In Process May 22, 2019 Order Expected January 2020 (1) Rates will be implemented in three steps, with implementation of step 1 rates effective October 1, 2018. Step 2 rates were effective on March 1, 2019, and step 3 rates will be effective on January 1, 2020. The IURC’s order also dismissed NIPSCO from phase 2 of the IURC’s TCJA investigation. (2) Rates as originally filed were implemented in February 2019 on an interim basis, subject to refund. The final approved rates, which replaced interim rates, were implemented in July 2019. (3) An order on the partial settlement agreement, including the resolution of outstanding TCJA impacts to rates is currently pending before the IURC. The as-filed request and partial settlement agreement also includes $83.6 million and $85.3 million , respectively, of reductions to the fuel component of base rates related to a proposed change in service structure.

Risk Management Activities (Tab

Risk Management Activities (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 December 31, 2018 Risk Management Assets - Current (1) Interest rate risk programs $ — $ — Commodity price risk programs 1.0 1.1 Total $ 1.0 $ 1.1 Risk Management Assets - Noncurrent (2) Interest rate risk programs $ — $ 18.5 Commodity price risk programs 4.3 4.4 Total $ 4.3 $ 22.9 Risk Management Liabilities - Current (3) Interest rate risk programs $ 46.4 $ — Commodity price risk programs 10.7 5.0 Total $ 57.1 $ 5.0 Risk Management Liabilities - Noncurrent Interest rate risk programs $ 78.1 $ 9.5 Commodity price risk programs 46.9 37.2 Total $ 125.0 $ 46.7 (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). (3) Presented in "Other accruals" on the Condensed Consolidated Balance Sheets (unaudited).

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 : Recurring Fair Value Measurements (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of September 30, 2019 Assets Risk management assets $ — $ 5.3 $ — $ 5.3 Available-for-sale securities — 145.7 — 145.7 Total $ — $ 151.0 $ — $ 151.0 Liabilities Risk management liabilities $ — $ 182.1 $ — $ 182.1 Total $ — $ 182.1 $ — $ 182.1 Recurring Fair Value Measurements (in millions) Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance as of December 31, 2018 Assets Risk management assets $ — $ 24.0 $ — $ 24.0 Available-for-sale securities — 138.3 — 138.3 Total $ — $ 162.3 $ — $ 162.3 Liabilities Risk management liabilities $ — $ 51.7 $ — $ 51.7 Total $ — $ 51.7 $ — $ 51.7
Schedule of Available-For-Sale Securities	The amortized cost, gross unrealized gains and losses and fair value of available-for-sale securities at September 30, 2019 and December 31, 2018 were: September 30, 2019 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities U.S. Treasury debt securities $ 31.1 $ 0.2 $ (0.1 ) $ 31.2 Corporate/Other debt securities 110.6 4.1 (0.2 ) 114.5 Total $ 141.7 $ 4.3 $ (0.3 ) $ 145.7 December 31, 2018 (in millions) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale securities U.S. Treasury debt securities $ 23.6 $ 0.1 $ (0.1 ) $ 23.6 Corporate/Other debt securities 117.7 0.4 (3.4 ) 114.7 Total $ 141.3 $ 0.5 $ (3.5 ) $ 138.3
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 Amount as of Dec. 31, 2018 Estimated Fair Value as of Dec. 31, 2018 Long-term debt (including current portion) $ 7,864.7 $ 8,865.2 $ 7,155.4 $ 7,228.3

Transfers Of Financial Assets (

Transfers Of Financial Assets (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 : (in millions) September 30, 2019 December 31, 2018 Gross Receivables $ 375.1 $ 694.4 Less: Receivables not transferred 115.0 295.2 Net receivables transferred $ 260.1 $ 399.2 Short-term debt due to asset securitization $ 260.1 $ 399.2

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following presents our goodwill balance allocated by segment as of September 30, 2019 : (in millions) Gas Distribution Operations Electric Operations Corporate and Other Total Goodwill $ 1,690.7 $ — $ — $ 1,690.7

Pension And Other Postretirem_2

Pension And Other Postretirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and 2018 : Pension Benefits Other Postretirement Benefits Three Months Ended September 30, (in millions) 2019 2018 2019 2018 Components of Net Periodic Benefit Cost (1) Service cost $ 7.3 $ 7.8 $ 1.3 $ 1.3 Interest cost 18.1 16.8 4.8 4.4 Expected return on assets (27.2 ) (35.4 ) (3.3 ) (3.7 ) Amortization of prior service credit — (0.1 ) (0.8 ) (1.0 ) Recognized actuarial loss 11.3 10.2 0.5 0.9 Settlement loss 1.9 8.3 — — Total Net Periodic Benefit Cost $ 11.4 $ 7.6 $ 2.5 $ 1.9 (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 (unaudited). Pension Benefits Other Postretirement Benefits Nine Months Ended September 30, (in millions) 2019 2018 2019 2018 Components of Net Periodic Benefit Cost (1) Service cost $ 21.9 $ 23.6 $ 3.9 $ 3.9 Interest cost 54.5 50.0 14.4 13.2 Expected return on assets (81.6 ) (107.9 ) (9.9 ) (11.1 ) Amortization of prior service credit — (0.3 ) (2.4 ) (3.0 ) Recognized actuarial loss 34.1 30.6 1.5 2.7 Settlement loss 1.9 11.8 — — Total Net Periodic Benefit Cost $ 30.8 $ 7.8 $ 7.5 $ 5.7 (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 (unaudited).
Schedule of Assumptions Used	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 at the measurement date of August 31, 2019: August 31, 2019 Weighted-average Assumption to Determine Benefit Obligation Discount rate 2.80 % Weighted-average Assumptions to Determine Net Periodic Benefit Costs for the period ended Discount rate - service cost 4.49 % Discount rate - interest cost 3.84 % Expected return on assets 5.70 %

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	9 Months Ended
	Sep. 30, 2019
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 2.74% and 2.96% at September 30, 2019 and December 31, 2018, respectively $ 505.0 $ 978.0 Accounts receivable securitization facility borrowings 260.1 399.2 Term loan weighted-average interest rate of 2.65% and 3.07% at September 30, 2019 and December 31, 2018, respectively 850.0 600.0 Total Short-Term Borrowings $ 1,615.1 $ 1,977.2

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Lease Cost	: Three Months Ended Nine Months Ended (in millions) Income Statement Classification 2019 2019 Finance lease cost Amortization of right-of-use assets Depreciation and amortization $ 3.6 $ 11.3 Interest on lease liabilities Interest expense, net 3.1 8.5 Total finance lease cost 6.7 19.8 Operating lease cost Operation and maintenance 5.3 12.3 Short-term lease cost Operation and maintenance 0.1 0.9 Total lease cost $ 12.1 $ 33.0
Right-of-Use Assets and Liabilities	Our right-of-use assets and liabilities are presented in the following lines on the Condensed Consolidated Balance Sheets (unaudited): (in millions) Balance Sheet Classification September 30, 2019 Assets Finance leases Net Property, Plant and Equipment $ 176.5 Operating leases Deferred charges and other 60.9 Total leased assets 237.4 Liabilities Current Finance leases Current portion of long-term debt 10.7 Operating leases Other accruals 10.5 Noncurrent Finance leases Long-term debt, excluding amounts due within one year 187.2 Operating leases Other noncurrent liabilities 50.5 Total lease liabilities $ 258.9
Lease Information	Other pertinent information related to leases was as follows: Nine Months Ended September 30, (in millions) 2019 Cash paid for amounts included in the measurement of lease liabilities Operating cash flows used for finance leases $ 8.4 Operating cash flows used for operating leases 11.8 Financing cash flows used for finance leases 7.7 Right-of-use assets obtained in exchange for lease obligations Finance leases 11.0 Operating leases $ 3.7 September 30, 2019 Weighted-average remaining lease term (years) Finance leases 15.5 Operating leases 9.7 Weighted-average discount rate Finance leases 6.0 % Operating leases 4.4 %
Lease Maturity	Maturities of our lease liabilities presented on a rolling 12-month basis were as follows: As of September 30, 2019, (in millions) Total Finance Leases Operating Leases Year 1 $ 37.7 $ 24.5 $ 13.2 Year 2 33.9 24.6 9.3 Year 3 32.8 24.6 8.2 Year 4 29.3 21.6 7.7 Year 5 27.6 20.6 7.0 Thereafter 247.8 214.8 33.0 Total lease payments 409.1 330.7 78.4 Less: Imputed interest (121.6 ) (107.0 ) (14.6 ) Less: Leases not yet commenced (1) (28.6 ) (25.8 ) (2.8 ) Total 258.9 197.9 61.0 Reported as of September 30, 2019 Short-term lease liabilities 21.2 10.7 10.5 Long-term lease liabilities 237.7 187.2 50.5 Total lease liabilities $ 258.9 $ 197.9 $ 61.0 (1) Expected payments include obligations for leases not yet commenced of approximately $28.6 million for interconnection facilities and corporate and field offices. The facilities will have lease terms between 8 years and 20 years , with estimated commencements in the fourth quarter of 2019 and in the third quarter of 2020.

Other Commitments And Conting_2

Other Commitments And Contingencies (Tables)	9 Months Ended
	Sep. 30, 2019
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" in our Condensed Statements of Consolidated Income (Loss) (unaudited). Year Ended Three Months Ended Nine Months Ended (in millions) December 31, 2018 September 30, 2019 Incident to Date Third-party claims $ 757 $ 1 $ 238 $ 995 Other incident-related costs 266 20 122 388 Total 1,023 21 360 1,383 Insurance recoveries recorded (135 ) — (535 ) (670 ) Impact to operation and maintenance expense $ 888 $ 21 $ (175 ) $ 713
Insurance Recoveries and Cash Collected	The following table presents activity related to our Greater Lawrence Incident insurance receivable. These balances are presented within "Accounts receivable" in our Condensed Consolidated Balance Sheets (unaudited): (in millions) Insurance receivable Balance, December 31, 2018 $ 130 Insurance recoveries recorded in first quarter of 2019 100 Cash collected from insurance recoveries in the first quarter of 2019 (108 ) Balance, March 31, 2019 122 Insurance recoveries recorded in the second quarter of 2019 435 Cash collected from insurance recoveries in the second quarter of 2019 (297 ) Balance, June 30, 2019 $ 260 Insurance recoveries recorded in third quarter of 2019 — Cash collected from insurance recoveries in the third quarter of 2019 (260 ) Balance, September 30, 2019 $ —

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2019
Other Comprehensive Income (Loss), Tax [Abstract]
Components Of Accumulated Other Comprehensive Loss	The following tables display the components of Accumulated Other Comprehensive Income (Loss): 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. Three Months Ended September 30, 2018 (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, 2018 $ (2.2 ) $ (1.7 ) $ (17.0 ) $ (20.9 ) Other comprehensive income before reclassifications — 21.6 1.0 22.6 Amounts reclassified from accumulated other comprehensive income 0.1 0.9 (0.2 ) 0.8 Net current-period other comprehensive income 0.1 22.5 0.8 23.4 Balance as of September 30, 2018 $ (2.1 ) $ 20.8 $ (16.2 ) $ 2.5 (1) All amounts are net of tax. Amounts in parentheses indicate debits. Nine Months Ended September 30, 2018 (in millions) Gains and Losses on Securities (1) Gains and Losses on Cash Flow Hedges (1) Pension and OPEB Items (1) Accumulated Other Comprehensive Income (Loss) (1 ) Balance as of January 1, 2018 $ 0.2 $ (29.4 ) $ (14.2 ) $ (43.4 ) Other comprehensive income (loss) before reclassifications (2.5 ) 70.8 1.0 69.3 Amounts reclassified from accumulated other comprehensive income (loss) 0.2 (14.3 ) 0.2 (13.9 ) Net current-period other comprehensive income (loss) (2.3 ) 56.5 1.2 55.4 Reclassification due to adoption of ASU 2018-02 — (6.3 ) (3.2 ) (9.5 ) Balance as of September 30, 2018 $ (2.1 ) $ 20.8 $ (16.2 ) $ 2.5 (1) All amounts are net of tax. Amounts in parentheses indicate debits.

Other, Net (Tables)

Other, Net (Tables)	9 Months Ended
	Sep. 30, 2019
Other, Net [Abstract]
Schedule of Other Nonoperating Income (Expense)	Three Months Ended Nine Months Ended (in millions) 2019 2018 2019 2018 Interest income $ 2.1 $ 1.4 $ 5.4 $ 4.2 AFUDC equity 2.9 5.0 7.1 12.6 Charitable contributions (1.1 ) (11.1 ) (4.0 ) (13.9 ) Pension and other postretirement non-service cost (2.8 ) 2.4 (8.7 ) 14.7 Interest rate swap settlement gain — — — 21.2 Miscellaneous 0.2 0.6 0.5 3.6 Total Other, net $ 1.3 $ (1.7 ) $ 0.3 $ 42.4

Business Segment Information (T

Business Segment Information (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Schedule Of Operating Income Derived From Revenues And Expenses By Segment	At September 30, 2019 , 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 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) 2019 2018 2019 2018 Operating Revenues Gas Distribution Operations Unaffiliated $ 463.6 $ 418.6 $ 2,506.2 $ 2,347.8 Intersegment 3.3 3.3 9.9 9.8 Total 466.9 421.9 2,516.1 2,357.6 Electric Operations Unaffiliated 467.7 476.2 1,304.9 1,304.4 Intersegment 0.2 0.2 0.6 0.6 Total 467.9 476.4 1,305.5 1,305.0 Corporate and Other Unaffiliated 0.2 0.2 0.6 0.6 Intersegment 116.9 116.4 342.2 346.6 Total 117.1 116.6 342.8 347.2 Eliminations (120.4 ) (119.9 ) (352.7 ) (357.0 ) Consolidated Operating Revenues $ 931.5 $ 895.0 $ 3,811.7 $ 3,652.8 Operating Income (Loss) Gas Distribution Operations $ (48.6 ) $ (455.2 ) $ 605.8 $ (94.4 ) Electric Operations 140.7 134.9 321.4 300.4 Corporate and Other (1.1 ) 4.4 1.5 (2.9 ) Consolidated Operating Income (Loss) $ 91.0 $ (315.9 ) $ 928.7 $ 203.1

Revenue Recognition (Narrative)

Revenue Recognition (Narrative) (Details)	9 Months Ended
	Sep. 30, 2019
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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	$ 891	$ 855.8	$ 3,694.7	$ 3,555.1
Other revenues		40.5	39.2	117	97.7
Total Operating Revenues		931.5	895	3,811.7	3,652.8
Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	451.2	406.5	2,462.7	2,317.6
Other revenues		12.4	12.1	43.5	30.2
Total Operating Revenues		463.6	418.6	2,506.2	2,347.8
Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	439.6	449.1	1,231.4	1,236.9
Other revenues		28.1	27.1	73.5	67.5
Total Operating Revenues		467.7	476.2	1,304.9	1,304.4
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]	437	411.7	2,012	1,922.6
Residential | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	288.3	257	1,638.6	1,540.3
Residential | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	148.7	154.7	373.4	382.3
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]	227.2	221.6	913.9	890.4
Commercial | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	90.9	80.9	543.2	516.2
Commercial | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	136.3	140.7	370.7	374.2
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]	196.8	192.6	651.7	629.4
Industrial | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	45.3	39	181.1	161.3
Industrial | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	151.5	153.6	470.6	468.1
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]	16.9	20.4	60.4	63.6
Off-system | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	16.9	20.4	60.4	63.6
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]	13.1	9.5	56.7	49.1
Miscellaneous | Gas Distribution Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	9.8	9.2	39.4	36.2
Miscellaneous | Electric Operations
Disaggregation of Revenue [Line Items]
Customer revenues	[1]	3.1	0.1	16.7	12.3
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 19

Revenue Recognition (Customer A

Revenue Recognition (Customer Accounts Receivable) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Customer Accounts Receivable, Billed (Less Reserve)	$ 297.1	$ 540.5
Customer Accounts Receivable, Unbilled (Less Reserve)	193.3	$ 349.1
Increase (Decrease) in Customer Accounts Receivable, Billed (Less Reserve)	(243.4)
Increase (Decrease) in Customer Accounts Receivable, Unbilled (Less Reserve)	$ (155.8)

Earnings Per Share (Details)

Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Denominator
Basic Average Common Shares Outstanding	374,100	363,900	373,796	352,100
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	374,100	363,900	375,195	352,100

Equity (Narrative) (Details)

Equity (Narrative) (Details) $ / shares in Units, $ in Millions	Aug. 01, 2019	Sep. 30, 2019USD ($)$ / sharesshares	Dec. 31, 2018$ / sharesshares	Sep. 30, 2019USD ($)$ / sharesshares
Common Stock, Shares Authorized		600,000,000	400,000,000	600,000,000
Common Stock, Shares, Outstanding		373,446,862	372,363,656	373,446,862
Preferred Stock, Shares Authorized		20,000,000	20,000,000	20,000,000
Preferred Stock, Shares Outstanding		440,000	420,000	440,000
Preferred Stock, Par or Stated Value Per Share | $ / shares		$ 0.01	$ 0.01	$ 0.01
At The Market Program
Number Of Equity Distribution Agreements	4
Common Stock Aggregate Sale Price | $		$ 434.4		$ 434.4
ATM Program Equity Remaining Available for Issuance | $				$ 200.7
Forward Agreement
Forward Contract Indexed to Issuer's Equity, Shares			4,708,098
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share | $ / shares			$ 26.55	$ 26.19
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value | $		$ 123.3		$ 123.3
Forward Agreement 19 [Member]
Forward Contract Indexed to Issuer's Equity, Shares		3,714,400
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share | $ / shares		$ 29.26		$ 28.98
Forward Contract Indexed to Issuer's Equity, Settlement Alternatives, Shares, at Fair Value | $		$ 107.6		$ 107.6
Series A Preferred Stock
Preferred Stock, Shares Outstanding		400,000		400,000
Series B Preferred Stock
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, 2019		Sep. 30, 2018		Sep. 30, 2019		Sep. 30, 2018		Jun. 30, 2019		Dec. 31, 2018		Jun. 30, 2018		Dec. 31, 2017
Class of Stock [Line Items]
Preferred Stock, Shares Outstanding	440,000				440,000						420,000
Shares outstanding	$ 5,848.5		$ 5,073.7		$ 5,848.5		$ 5,073.7		$ 5,976.2		$ 5,750.9		$ 5,463		$ 4,320.1
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		$ 28.88		$ 56.50		$ 28.88
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		$ 0		$ 1,674.65		$ 0
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	$ 880	[1]	$ 393.9	[2]	$ 880	[1]	$ 393.9	[2]	$ 880	[1]	880	[1]	$ 394.4	[2]	$ 0	[2]
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]	Series A and Series B shares have an aggregate liquidation preference of $400M and $500M , respectively. See Note 5 , "Equity" for additional information.
[2]	Series A shares have an aggregate liquidation preference of $400M . See Note 5 , "Equity" for additional information.

Regulatory Matters (Schedule of

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

Oct. 18, 2019

Oct. 15, 2019

Aug. 21, 2019

Aug. 15, 2019

Jun. 25, 2019

May 29, 2019

May 22, 2019

Apr. 17, 2019

Feb. 28, 2019

Jan. 29, 2019

Nov. 30, 2018

Nov. 01, 2018

Oct. 31, 2018

Oct. 15, 2018

Aug. 28, 2018

Aug. 17, 2018

Dec. 01, 2017

Sep. 27, 2017

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Adjustment

$ 5.2

Columbia Of Ohio | 2019 IRP

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[1]

$ 18.2

Regulatory Net Capital Expenditures Included In Filing

[1]

199.6

Columbia Of Ohio | 2018 CEP

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 74.5

Regulatory Net Capital Expenditures Included In Filing

$ 659.9

Columbia Of Ohio | 2019 CEP

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

15

Regulatory Net Capital Expenditures Included In Filing

$ 121.7

NIPSCO - Gas

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 107.3

Public Utilities, Requested Rate Increase (Decrease), Amount

[2]

$ 138.1

NIPSCO - Gas | TDSIC-9

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[1],[3]

(10.6)

Regulatory Net Capital Expenditures Included In Filing

[1],[3]

54.4

NIPSCO - Gas | TDSIC 10

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[4]

$ 1.6

Regulatory Net Capital Expenditures Included In Filing

[4]

$ 12.4

NIPSCO - Gas | FMCA 1

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[5]

$ 9.9

Regulatory Net Capital Expenditures Included In Filing

[5]

$ 1.5

NIPSCO - Gas | FMCA 2

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[5]

$ (3.5)

Regulatory Net Capital Expenditures Included In Filing

[5]

$ 1.8

Columbia Of Massachusetts | 2019 GSEP

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[6]

$ 10.7

Regulatory Net Capital Expenditures Included In Filing

[6]

64

Columbia Of Virginia

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

1.3

Public Utilities, Requested Rate Increase (Decrease), Amount

[7]

$ 14.2

Columbia Of Virginia | 2019 SAVE

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 2.4

Regulatory Net Capital Expenditures Included In Filing

$ 36

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

$ 48.3

Columbia Of Kentucky | 2019 AMRP

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 3.6

Regulatory Net Capital Expenditures Included In Filing

$ 30.1

Columbia Of Maryland

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 2.5

Columbia Of Maryland | 2019 STRIDE

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

$ 1.2

Regulatory Net Capital Expenditures Included In Filing

$ 15.9

NIPSCO - Electric

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Adjustment

83.6

Public Utilities, Approved Rate Increase (Decrease), Amount

(45)

Public Utilities, Requested Rate Increase (Decrease), Amount

[8]

$ 21.4

NIPSCO - Electric | TDSIC 5

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[1]

$ 15.9

Regulatory Net Capital Expenditures Included In Filing

[1]

$ 58.8

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 11

Regulatory Matters [Line Items]

Public Utilities, Approved Rate Increase (Decrease), Amount

[5]

$ 0.9

Regulatory Net Capital Expenditures Included In Filing

[5]

$ 22.4

Subsequent Event | Columbia Of Kentucky | 2020 AMRP

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

$ 4.2

Regulatory Net Capital Expenditures Included In Filing

$ 40.4

Subsequent Event | NIPSCO - Electric | FMCA 12

Regulatory Matters [Line Items]

Public Utilities, Requested Rate Increase (Decrease), Amount

[5]

$ 1.6

Regulatory Net Capital Expenditures Included In Filing

[5]

$ 4.7

[1]

Incremental revenue is net of amounts due back to customers as a result of the TCJA.

[2]

Rates will be implemented in three steps, with implementation of step 1 rates effective October 1, 2018. Step 2 rates were effective on March 1, 2019, and step 3 rates will be effective on January 1, 2020. The IURC’s order also dismissed NIPSCO from phase 2 of the IURC’s TCJA investigation.

[3]

Incremental revenue is net of $5.2 million of adjustments in the TDSIC-9 settlement.

[4]

Incremental capital and revenue are net of amounts included in the step 2 base rate implementation.

[5]

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

[6]

Incremental capital investment anticipated to be lower than $64.0 million for 2019.

[7]

Rates as originally filed were implemented in February 2019 on an interim basis, subject to refund. The final approved rates, which replaced interim rates, were implemented in July 2019.

[8]

An order on the partial settlement agreement, including the resolution of outstanding TCJA impacts to rates is currently pending before the IURC. The as-filed request and partial settlement agreement also includes $83.6 million and $85.3 million , respectively, of reductions to the fuel component of base rates related to a proposed change in service structure.

Regulatory Matters (Rate Case A

Regulatory Matters (Rate Case Action) (Details) - USD ($) $ in Millions		May 22, 2019	Oct. 31, 2018	Aug. 28, 2018	Sep. 27, 2017
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Adjustment				$ 5.2
NIPSCO - Gas
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	[1]				$ 138.1
Public Utilities, Approved Rate Increase (Decrease), Amount					$ 107.3
Columbia Of Virginia
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	[2]			14.2
Public Utilities, Approved Rate Increase (Decrease), Amount				$ 1.3
NIPSCO - Electric
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount	[3]		$ 21.4
Public Utilities, Approved Rate Increase (Decrease), Amount			(45)
Public Utilities, Requested Rate Increase (Decrease), Adjustment			83.6
Public Utilities, Approved Rate Increase (Decrease), Adjustment			$ 85.3
Columbia Of Maryland
Rate Case Action [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Amount		$ 2.5
[1]	Rates will be implemented in three steps, with implementation of step 1 rates effective October 1, 2018. Step 2 rates were effective on March 1, 2019, and step 3 rates will be effective on January 1, 2020. The IURC’s order also dismissed NIPSCO from phase 2 of the IURC’s TCJA investigation.
[2]	Rates as originally filed were implemented in February 2019 on an interim basis, subject to refund. The final approved rates, which replaced interim rates, were implemented in July 2019.
[3]	An order on the partial settlement agreement, including the resolution of outstanding TCJA impacts to rates is currently pending before the IURC. The as-filed request and partial settlement agreement also includes $83.6 million and $85.3 million , respectively, of reductions to the fuel component of base rates related to a proposed change in service structure.

Risk Management Activities (Nar

Risk Management Activities (Narrative) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
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
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, 2019	Dec. 31, 2018
Risk Management Assets Current
Derivatives, Fair Value [Line Items]
Risk management assets	[1]	$ 1	$ 1.1
Risk Management Assets Noncurrent
Derivatives, Fair Value [Line Items]
Risk management assets	[2]	4.3	22.9
Risk Management Liabilities Current
Derivatives, Fair Value [Line Items]
Risk management liabilities	[3]	57.1	5
Risk Management Liabilities Noncurrent
Derivatives, Fair Value [Line Items]
Risk management liabilities		125	46.7
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	18.5
Interest Rate Risk | Risk Management Liabilities Current
Derivatives, Fair Value [Line Items]
Risk management liabilities	[3]	46.4	0
Interest Rate Risk | Risk Management Liabilities Noncurrent
Derivatives, Fair Value [Line Items]
Risk management liabilities		78.1	9.5
Commodity Price Risk Programs | Risk Management Assets Current
Derivatives, Fair Value [Line Items]
Risk management assets	[1]	1	1.1
Commodity Price Risk Programs | Risk Management Assets Noncurrent
Derivatives, Fair Value [Line Items]
Risk management assets	[2]	4.3	4.4
Commodity Price Risk Programs | Risk Management Liabilities Current
Derivatives, Fair Value [Line Items]
Risk management liabilities	[3]	10.7	5
Commodity Price Risk Programs | Risk Management Liabilities Noncurrent
Derivatives, Fair Value [Line Items]
Risk management liabilities		$ 46.9	$ 37.2
[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).
[3]	Presented in "Other accruals" on the Condensed Consolidated Balance Sheets (unaudited).

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Fair Value Disclosure [Line Items]
Transfers between Fair Value Hierarchies	$ 0	$ 0
Material Level 3 Changes	0	$ 0
Fair Value, Assets and Liabilities Measured on a Non-Recurring Basis	0
U.S. Treasury debt securities
Fair Value Disclosure [Line Items]
Available-for-sale Securities, Maturities, Next Twelve Months, Fair Value	6.8
Corporate/Other debt securities
Fair Value Disclosure [Line Items]
Available-for-sale Securities, Maturities, Next Twelve Months, Fair Value	$ 4.5

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, 2019	Dec. 31, 2018
Assets
Total	$ 151	$ 162.3
Liabilities
Total	182.1	51.7
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	5.3	24
Available-for-sale securities	145.7	138.3
Total	151	162.3
Liabilities
Risk management liabilities	182.1	51.7
Total	182.1	51.7
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	145.7	138.3
Risk management assets
Assets
Risk management assets	5.3	24
Liabilities
Risk management liabilities	$ 182.1	$ 51.7

Fair Value (Available-For-Sale

Fair Value (Available-For-Sale Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value Disclosure [Line Items]
Amortized Cost	$ 141.7	$ 141.3
Gross Unrealized Gains	4.3	0.5
Gross Unrealized Losses	(0.3)	(3.5)
Fair Value	145.7	138.3
U.S. Treasury debt securities
Fair Value Disclosure [Line Items]
Amortized Cost	31.1	23.6
Gross Unrealized Gains	0.2	0.1
Gross Unrealized Losses	(0.1)	(0.1)
Fair Value	31.2	23.6
Corporate/Other debt securities
Fair Value Disclosure [Line Items]
Amortized Cost	110.6	117.7
Gross Unrealized Gains	4.1	0.4
Gross Unrealized Losses	(0.2)	(3.4)
Fair Value	$ 114.5	$ 114.7

Fair Value (Carrying Amount And

Fair Value (Carrying Amount And Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Long-term Debt (including current portion), Carrying Amount	$ 7,864.7	$ 7,155.4
Long-term debt (including current portion), Estimated Fair Value	$ 8,865.2	$ 7,228.3

Transfers Of Financial Assets_2

Transfers Of Financial Assets (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)
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			$ 139.1	$ 71.7
Securitization Transaction Fees	$ 0.6	$ 0.4	2	$ 1.9
Accounts Receivable Program
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Seasonal Limit	$ 270		$ 270

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, 2019	Dec. 31, 2018
Gross Receivables	$ 375.1	$ 694.4
Less: Receivables not transferred	115	295.2
Net receivables transferred	260.1	399.2
Accounts receivable securitization facility borrowings	$ 260.1	$ 399.2

Goodwill (Narrative) (Details)

Goodwill (Narrative) (Details) - USD ($) $ in Millions	4 Months Ended
	May 01, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill, Impairment Loss	$ 0
Goodwill		$ 1,690.7		$ 1,690.7
Columbia Of Massachusetts
Goodwill [Line Items]
Goodwill			$ 204.8

Goodwill (Schedule of Goodwill)

Goodwill (Schedule of Goodwill) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill	$ 1,690.7	$ 1,690.7
Gas Distribution Operations
Goodwill [Line Items]
Goodwill	1,690.7
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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective income tax rates	283.30%	21.80%	18.80%	40.30%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate			21.00%
Increase (Decrease) in Effective Tax Rate	261.50%		(21.50%)
Changes to Liability for Uncertain Tax Positions			$ 0

Pension And Other Postretirem_3

Pension And Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Aug. 31, 2019
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions				$ 2.1
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[1]	$ (1.9)	$ (8.3)	(1.9)	$ (11.8)
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement				2.2
Change in Regulatory Assets Due to Interim Measurement						$ (4)
Change in Accumulated Other Comprehensive Income Due to Interim Measurement						0.1
Change to Defined Benefit Plan Net Periodic Costs Due to Interim Measurement						$ (0.7)
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions				17.8
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	[1]	$ 0	$ 0	$ 0	$ 0
[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 (unaudited).

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	[1]	$ 7.3	$ 7.8	$ 21.9	$ 23.6
Interest cost	[1]	18.1	16.8	54.5	50
Expected return on assets	[1]	(27.2)	(35.4)	(81.6)	(107.9)
Amortization of prior service credit	[1]	0	(0.1)	0	(0.3)
Recognized actuarial loss	[1]	11.3	10.2	34.1	30.6
Settlement Loss	[1]	1.9	8.3	1.9	11.8
Total Net Periodic Benefits Cost		11.4	7.6	30.8	7.8
Other Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service Cost	[1]	1.3	1.3	3.9	3.9
Interest cost	[1]	4.8	4.4	14.4	13.2
Expected return on assets	[1]	(3.3)	(3.7)	(9.9)	(11.1)
Amortization of prior service credit	[1]	(0.8)	(1)	(2.4)	(3)
Recognized actuarial loss	[1]	0.5	0.9	1.5	2.7
Settlement Loss	[1]	0	0	0	0
Total Net Periodic Benefits Cost		$ 2.5	$ 1.9	$ 7.5	$ 5.7
[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 (unaudited).

Pension And Other Postretirem_5

Pension And Other Postretirement Benefits Schedule of Assumptions Used (Details) - Pension Plan	8 Months Ended
	Aug. 31, 2019Rate
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.80%
Discount rate -service cost	4.49%
Discount rate - interest cost	3.84%
Expected return on assets	5.70%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Aug. 12, 2019	Apr. 01, 2019
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			5.85%
5.85% Notes Due 2019
Debt Instrument [Line Items]
Debt Instrument, Repurchase Amount			$ 41
2.95% Notes Due 2029
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.95%
Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 750
Senior Notes | 2.95% Notes Due 2029
Debt Instrument [Line Items]
Proceeds from Debt, Net of Issuance Costs	$ 742.4

Short-Term Borrowings (Narrativ

Short-Term Borrowings (Narrative) (Details) - USD ($) $ in Millions	Apr. 17, 2019	Sep. 30, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Commercial paper outstanding		$ 505	$ 978
Accounts receivable securitization facility borrowings		260.1	399.2
Revolving Credit Facility
Short-term Debt [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		1,850
Long-term Line of Credit		0	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	600
Debt Instrument, Basis Spread on Variable Rate	0.60%
Term Loan | Debt Oustanding
Short-term Debt [Line Items]
Term Loan	$ 850
Maximum | Term Loan
Short-term Debt [Line Items]
Term Loan	$ 850		$ 600

Short-Term Borrowings (Schedule

Short-Term Borrowings (Schedule Of Short-Term Borrowings) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Commercial paper weighted-average interest rate of 2.74% and 2.96% at September 30, 2019 and December 31, 2018, respectively	$ 505	$ 978
Accounts receivable securitization facility borrowings	260.1	399.2
Total short-term borrowings	$ 1,615.1	$ 1,977.2
Commercial Paper
Short-term Debt [Line Items]
Short-term Debt, Weighted Average Interest Rate, at Point in Time	2.74%	2.96%
Term Loan
Short-term Debt [Line Items]
Term loan weighted-average interest rate of 2.65% and 3.07% at September 30, 2019 and December 31, 2018, respectively	$ 850	$ 600
Short-term Debt, Weighted Average Interest Rate, at Point in Time	2.65%	3.07%

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset		$ 60.9	$ 57
Lessee, Lease Renewal Term		25 years
Lessee, Operating Lease, Renewal Term		1 year
Lessee, Finance Lease, Term of Contract		4 years
Leases Not Yet Commenced	[1]	$ 28.6
Lessee, Finance Lease, Lease Not yet Commenced, Term of Contract		8 years
Capital Leases, Future Minimum Payments, Interest Included in Payments				$ 114.6
Operating Leases, Future Minimum Payments Due, Next Twelve Months	[2]			11
Operating Leases, Future Minimum Payments, Due in Two Years	[2]			7.3
Operating Leases, Future Minimum Payments, Due in Three Years	[2]			6.1
Operating Leases, Future Minimum Payments, Due in Four Years	[2]			4.2
Operating Leases, Future Minimum Payments, Due in Five Years	[2]			2.8
Operating Leases, Future Minimum Payments, Due Thereafter	[2]			14.5
Fleet Lease
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year
Operating Leases, Future Minimum Payments Due, Next Twelve Months				26.7
Operating Leases, Future Minimum Payments, Due in Two Years				22.4
Operating Leases, Future Minimum Payments, Due in Three Years				16.6
Operating Leases, Future Minimum Payments, Due in Four Years				12.3
Operating Leases, Future Minimum Payments, Due in Five Years				9.3
Operating Leases, Future Minimum Payments, Due Thereafter				$ 8.8
Interconnection facilities
Lessee, Lease, Description [Line Items]
Leases Not Yet Commenced	[1]	$ 28.6
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year
Minimum | Office Lease
Lessee, Lease, Description [Line Items]
Remaining Lease Term		1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		3 years
Lessee, Finance Lease, Lease Not yet Commenced, Term of Contract		20 years
Maximum | Office Lease
Lessee, Lease, Description [Line Items]
Remaining Lease Term		25 years
[1]	Expected payments include obligations for leases not yet commenced of approximately $28.6 million for interconnection facilities and corporate and field offices. The facilities will have lease terms between 8 years and 20 years , with estimated commencements in the fourth quarter of 2019 and in the third quarter of 2020.
[2]	Operating lease balances do not include obligations for possible fleet vehicle lease renewals beyond the initial lease term. While we have the ability to renew these leases beyond the initial term, we are not reasonably certain to do so. Expected payments are $26.7 million in 2019, $22.4 million in 2020, $16.6 million in 2021, $12.3 million in 2022, $9.3 million in 2023 and $8.8 million thereafter.

Leases (Lease Cost) (Details)

Leases (Lease Cost) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Finance lease cost
Amortization of right-of-use assets	$ 3.6	$ 11.3
Interest on lease liabilities	3.1	8.5
Total finance lease cost	6.7	19.8
Operating lease cost	5.3	12.3
Short-term lease cost	0.1	0.9
Total lease cost	$ 12.1	$ 33

Leases (Right-of-Use Assets and

Leases (Right-of-Use Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:NetPropertyPlantandEquipment
Finance Lease, Right-of-Use Asset	$ 176.5
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:DeferredChargesAndOther
Operating Lease, Right-of-Use Asset	$ 60.9	$ 57
Total leased assets	$ 237.4
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:Currentportionoflong-termdebt
Finance Lease, Liability, Current	$ 10.7
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherAccruals
Operating Lease, Liability, Current	$ 10.5
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:Long-termDebtExcludingAmountsDueWithinOneYear
Finance Lease, Liability, Noncurrent	$ 187.2
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherNoncurrentLiabilities
Operating Lease, Liability, Noncurrent	$ 50.5
Total Lease Liability	$ 258.9

Leases (Lease Information) (Det

Leases (Lease Information) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)Rate
Leases [Abstract]
Finance Lease, Interest Payment on Liability	$ 8.4
Operating Lease, Payments	11.8
Finance Lease, Principal Payments	7.7
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	11
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 3.7
Finance Lease, Weighted Average Remaining Lease Term	15 years 6 months
Operating Lease, Weighted Average Remaining Lease Term	9 years 8 months 12 days
Finance Lease, Weighted Average Discount Rate, Percent | Rate	6.00%
Operating Lease, Weighted Average Discount Rate, Percent | Rate	4.40%

Leases (Lease Maturity) (Detail

Leases (Lease Maturity) (Details) - USD ($) $ in Millions		Sep. 30, 2019	Dec. 31, 2018
Lease Maturity [Line Items]
Total Future Minimum Lease Payments Due, Next Twelve Months		$ 37.7	$ 34
Total Future Minimum Lease Payments, Due in Two Years		33.9	29.8
Total Future Minimum Lease Payments, Due in Three Years		32.8	28.7
Total Future Minimum Lease Payments, Due in Four Years		29.3	26.3
Total Future Minimum Lease Payments, Due in Five Years		27.6	22.6
Total Future Minimum Lease Payments, Due Thereafter		247.8	226.9
Total Future Minimum Lease Payments Due		409.1	$ 368.3
Undiscounted Excess Amount		(121.6)
Total Lease Liability		258.9
Short-term Lease Liability		21.2
Long-term Lease Liability		237.7
Finance Lease, Liability, Current		10.7
Finance Lease, Liability, Noncurrent		187.2
Leases Not Yet Commenced	[1]	(28.6)
Operating Lease, Liability, Current		10.5
Operating Lease, Liability, Noncurrent		50.5
Finance Lease
Lease Maturity [Line Items]
Finance Lease, Liability, Payments, Due in Next Rolling Twelve Months		24.5
Finance Lease, Liability, Payments, Due in Rolling Year Two		24.6
Finance Lease, Liability, Payments, Due in Rolling Year Three		24.6
Finance Lease, Liability, Payments, Due in Rolling Year Four		21.6
Finance Lease, Liability, Payments, Due in Rolling Year Five		20.6
Finance Lease, Liability, Payments, Due in Rolling after Year Five		214.8
Finance Lease, Liability, Payment, Due		330.7
Finance Lease, Liability, Undiscounted Excess Amount		(107)
Finance Lease, Liability		197.9
Finance Lease, Liability, Current		10.7
Finance Lease, Liability, Noncurrent		187.2
Leases Not Yet Commenced	[1]	(25.8)
Operating Lease
Lease Maturity [Line Items]
Lessee, Operating Lease, Liability, Payments, Due Next Rolling Twelve Months		13.2
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Two		9.3
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Three		8.2
Lessee, Operating Lease, Liability, Payments, Due Year Four		7.7
Lessee, Operating Lease, Liability, Payments, Due in Rolling Year Five		7
Lessee, Operating Lease, Liability, Payments, Due after Rolling Year Five		33
Lessee, Operating Lease, Liability, Payments, Due		78.4
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		(14.6)
Leases Not Yet Commenced	[1]	(2.8)
Operating Lease, Liability		61
Operating Lease, Liability, Current		10.5
Operating Lease, Liability, Noncurrent		$ 50.5
[1]	Expected payments include obligations for leases not yet commenced of approximately $28.6 million for interconnection facilities and corporate and field offices. The facilities will have lease terms between 8 years and 20 years , with estimated commencements in the fourth quarter of 2019 and in the third quarter of 2020.

Leases (Lease Maturity under AS

Leases (Lease Maturity under ASC 840) (Details) - USD ($) $ in Millions		Sep. 30, 2019	Dec. 31, 2018
Leases [Abstract]
Total Future Minimum Lease Payments Due, Next Twelve Months		$ 37.7	$ 34
Total Future Minimum Lease Payments, Due in Two Years		33.9	29.8
Total Future Minimum Lease Payments, Due in Three Years		32.8	28.7
Total Future Minimum Lease Payments, Due in Four Years		29.3	26.3
Total Future Minimum Lease Payments, Due in Five Years		27.6	22.6
Total Future Minimum Lease Payments, Due Thereafter		247.8	226.9
Total Future Minimum Lease Payments Due		$ 409.1	368.3
Capital Leases, Future Minimum Payments Due, Next Twelve Months	[1]		23
Capital Leases, Future Minimum Payments Due in Two Years	[1]		22.5
Capital Leases, Future Minimum Payments Due in Three Years	[1]		22.6
Capital Leases, Future Minimum Payments Due in Four Years	[1]		22.1
Capital Leases, Future Minimum Payments Due in Five Years	[1]		19.8
Capital Leases, Future Minimum Payments Due Thereafter	[1]		212.4
Capital Leases, Future Minimum Payments Due	[1]		322.4
Operating Leases, Future Minimum Payments Due, Next Twelve Months	[2]		11
Operating Leases, Future Minimum Payments, Due in Two Years	[2]		7.3
Operating Leases, Future Minimum Payments, Due in Three Years	[2]		6.1
Operating Leases, Future Minimum Payments, Due in Four Years	[2]		4.2
Operating Leases, Future Minimum Payments, Due in Five Years	[2]		2.8
Operating Leases, Future Minimum Payments, Due Thereafter	[2]		14.5
Operating Leases, Future Minimum Payments Due	[2]		$ 45.9
[1]	Capital lease payments shown above are inclusive of interest totaling $114.6 million .
[2]	Operating lease balances do not include obligations for possible fleet vehicle lease renewals beyond the initial lease term. While we have the ability to renew these leases beyond the initial term, we are not reasonably certain to do so. Expected payments are $26.7 million in 2019, $22.4 million in 2020, $16.6 million in 2021, $12.3 million in 2022, $9.3 million in 2023 and $8.8 million thereafter.

Other Commitments And Conting_3

Other Commitments And Contingencies (Narrative) (Details)	Nov. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 27, 2019	Jul. 26, 2019USD ($)
Other Commitments And Contingencies [Line Items]
Proceeds From Insurance Settlement		$ 260,000,000	$ 297,000,000	$ 108,000,000
Homes and Business Evacuated								150
Number Of Customers							1,400
Litigation Settlement, Amount Awarded to Other Party									$ 143,000,000
Costs Resulting from the Greater Lawrence Incident		21,000,000			$ 1,023,000,000	$ 360,000,000	$ 1,383,000,000
Liability Insurance for Damages		800,000,000				800,000,000	800,000,000
Recorded reserves to cover environmental remediation at various sites		107,500,000			101,200,000	107,500,000	107,500,000
Other incident-related costs		20,000,000			266,000,000	122,000,000	388,000,000
Property Insurance		$ 300,000,000				$ 300,000,000	$ 300,000,000
MGP Sites
Other Commitments And Contingencies [Line Items]
Number of waste disposal sites identified by program		63				63	63
Liability for Estimated Remediation Costs		$ 103,900,000			97,500,000	$ 103,900,000	$ 103,900,000
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
Consent Order Fine	$ 75,000
Miles of Affected Cast Iron and Bare Steel Pipeline System		45
Pipeline Replacement Expenses							255,000,000
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
Costs Resulting from the Greater Lawrence Incident						1,020,000,000
Other incident-related costs							440,000,000
Estimated Capital Cost of the Pipeline Replacement		$ 260,000,000				260,000,000	260,000,000
Minimum | Columbia Of Massachusetts
Other Commitments And Contingencies [Line Items]
Costs Resulting from the Greater Lawrence Incident						995,000,000
Other incident-related costs							430,000,000
Estimated Capital Cost of the Pipeline Replacement		255,000,000				255,000,000	255,000,000
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

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	13 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2019	Sep. 30, 2019
Expense and Insurance Recoveries [Line Items]
Third-party claims	$ 1			$ 757	$ 238	$ 995
Other incident-related costs	20			266	122	388
Total	21			1,023	360	1,383
Insurance recoveries recorded	0	$ (435)	$ (100)	(135)	(535)	(670)
Impact to operation and maintenance expense	$ 21			$ 888	$ (175)	$ 713

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			4 Months Ended	9 Months Ended	13 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2019	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Insurance Settlements Receivable	$ 0	$ 260	$ 122	$ 130	$ 0	$ 0
Insurance recoveries recorded	0	435	100	$ 135	$ 535	$ 670
Cash collected from insurance recoveries	$ (260)	$ (297)	$ (108)

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	$ (80.8)	$ (20.9)	$ (37.2)	$ (43.4)
Other Comprehensive Income before reclassifications	[1]	(49.6)	22.6	(93.9)	69.3
Amounts reclassified from accumulated other comprehensive loss	[1]	0.1	0.8	0.8	(13.9)
Net current-period other comprehensive income (loss)	[1]	(49.5)	23.4	(93.1)	55.4
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[1]					$ (9.5)
Ending Balance	[1]	(130.3)	2.5	(130.3)	2.5
Gains and Losses on Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	2.5	(2.2)	(2.4)	0.2
Other Comprehensive Income before reclassifications	[1]	0.9	0	5.9	(2.5)
Amounts reclassified from accumulated other comprehensive loss	[1]	(0.2)	0.1	(0.3)	0.2
Net current-period other comprehensive income (loss)	[1]	0.7	0.1	5.6	(2.3)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[1]					0
Ending Balance	[1]	3.2	(2.1)	3.2	(2.1)
Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	(62.8)	(1.7)	(13)	(29.4)
Other Comprehensive Income before reclassifications	[1]	(50.7)	21.6	(100.5)	70.8
Amounts reclassified from accumulated other comprehensive loss	[1]	0.1	0.9	0.1	(14.3)
Net current-period other comprehensive income (loss)	[1]	(50.6)	22.5	(100.4)	56.5
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[1]					(6.3)
Ending Balance	[1]	(113.4)	20.8	(113.4)	20.8
Pension and OPEB Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	[1]	(20.5)	(17)	(21.8)	(14.2)
Other Comprehensive Income before reclassifications	[1]	0.2	1	0.7	1
Amounts reclassified from accumulated other comprehensive loss	[1]	0.2	(0.2)	1	0.2
Net current-period other comprehensive income (loss)	[1]	0.4	0.8	1.7	1.2
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[1]					$ (3.2)
Ending Balance	[1]	$ (20.1)	$ (16.2)	$ (20.1)	$ (16.2)
[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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other, Net [Abstract]
Interest income	$ 2.1	$ 1.4	$ 5.4	$ 4.2
AFUDC equity	2.9	5	7.1	12.6
Charitable Contributions	(1.1)	(11.1)	(4)	(13.9)
Pension and other postretirement non-service cost	(2.8)	2.4	(8.7)	14.7
Interest rate swap settlement gain	0	0	0	21.2
Miscellaneous	0.2	0.6	0.5	3.6
Other, net	$ 1.3	$ (1.7)	$ 0.3	$ 42.4

Business Segment Information (N

Business Segment Information (Narrative) (Details)	9 Months Ended
	Sep. 30, 2019
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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenues	$ 931.5	$ 895	$ 3,811.7	$ 3,652.8
Consolidated Operating Income (Loss)	91	(315.9)	928.7	203.1
Gas Distribution Operations
Segment Reporting Information [Line Items]
Revenues	466.9	421.9	2,516.1	2,357.6
Consolidated Operating Income (Loss)	(48.6)	(455.2)	605.8	(94.4)
Gas Distribution Operations | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	463.6	418.6	2,506.2	2,347.8
Gas Distribution Operations | Intersegment
Segment Reporting Information [Line Items]
Revenues	3.3	3.3	9.9	9.8
Electric Operations
Segment Reporting Information [Line Items]
Revenues	467.9	476.4	1,305.5	1,305
Consolidated Operating Income (Loss)	140.7	134.9	321.4	300.4
Electric Operations | Unaffiliated
Segment Reporting Information [Line Items]
Revenues	467.7	476.2	1,304.9	1,304.4
Electric Operations | Intersegment
Segment Reporting Information [Line Items]
Revenues	0.2	0.2	0.6	0.6
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	117.1	116.6	342.8	347.2
Consolidated Operating Income (Loss)	(1.1)	4.4	1.5	(2.9)
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	116.9	116.4	342.2	346.6
Eliminations
Segment Reporting Information [Line Items]
Revenues	$ (120.4)	$ (119.9)	$ (352.7)	$ (357)