Additional Balance Sheet & Operational Information (Tables)

12 Months Ended

Dec. 31, 2017

Additional Balance Sheet and Operational Information [Abstract]

Summary of inventories

Inventories consist of the following:

	At December 31,
(In millions)	2017		2016
Gas in storage – at LIFO cost	$	36.0	$	37.0
Coal & oil for electric generation - at average cost	43.1		42.6
Materials & supplies	46.2		48.9
Other	1.3		1.4
Total inventories	$	126.6	$	129.9

Summary of prepayments and other current assets

Prepayments & other current assets consist of the following:

	At December 31,
(In millions)	2017		2016
Prepaid gas delivery service	$	26.6	$	26.4
Prepaid taxes	3.8		8.2
Other prepayments & current assets	16.6		18.1
Total prepayments & other current assets	$	47.0	$	52.7

Schedule of investments in unconsolidated affiliates

Investments in unconsolidated affiliates consist of the following:

	At December 31,
(In millions)	2017		2016
ProLiance Holdings, LLC	$	18.9	$	19.2
Other nonutility partnerships & corporations	0.6		1.0
Other utility investments	0.2		0.2
Total investments in unconsolidated affiliates	$	19.7	$	20.4

Other utility and corporate investments in the consolidated balance sheets

Other utility & corporate investments consist of the following:

	At December 31,
(In millions)	2017		2016
Cash surrender value of life insurance policies	$	42.2	$	33.1
Restricted cash & other investments	1.5		1.0
Total other utility & corporate investments	$	43.7	$	34.1

Goodwill by operating segment

Goodwill by operating segment follows:

	At December 31,
(In millions)	2017		2016
Utility Group
Gas Utility Services	$	205.0	$	205.0
Nonutility Group
Infrastructure Services	58.8		58.8
Energy Services	29.7		29.7
Consolidated goodwill	$	293.5	$	293.5

Accrued Liabilities

Accrued liabilities consist of the following:

	At December 31,
(In millions)	2017		2016
Refunds to customers & customer deposits	$	51.4	$	49.4
Accrued taxes	55.7		46.5
Accrued interest	19.6		18.2
Deferred compensation & post retirement benefits	6.4		6.6
Accrued salaries & other	89.2		87.0
Total accrued liabilities	$	222.3	$	207.7

Asset retirement obligation

Asset retirement obligations included in Deferred credits and other liabilities in the Consolidated Balance Sheets roll forward as follows:

(In millions)	2017			2016
Asset retirement obligation, January 1	$	106.7		$	82.0
Accretion	4.3			3.8
Changes in estimates, net of cash payments	(4.0		)	20.9
Asset retirement obligation, December 31	107.0			106.7

Equity in earnings (losses) of unconsolidated affiliates

Equity in earnings (losses) of unconsolidated affiliates consists of the following:

	Year Ended December 31,
(In millions)	2017			2016			2015
ProLiance Holdings, LLC	$	(0.3	)	$	(0.5	)	$	(0.8	)
Other	(0.8		)	0.3			0.2
Total equity in earnings (losses) of unconsolidated affiliates	$	(1.1	)	$	(0.2	)	$	(0.6	)

Other, net in the consolidated statements of income

Other income (expense) – net consists of the following:

	Year Ended December 31,
(In millions)	2017		2016		2015
AFUDC – borrowed funds	$	24.8	$	20.3	$	16.3
AFUDC – equity funds	2.6		2.2		2.6
Nonutility plant capitalized interest	1.2		1.0		0.4
Interest income, net	1.0		1.3		1.3
Other nonutility investment impairment charges	—		—		(0.1		)
All other income	3.2		3.9		(0.2		)
Total other income – net	$	32.8	$	28.7	$	20.3

Supplemental cash flow information

Supplemental Cash Flow Information:

	Year Ended December 31,
(In millions)	2017		2016			2015
Cash paid (received) for:
Interest	$	86.4	$	86.6		$	84.2
Income taxes	9.6		(3.6		)	4.8