Guarantee of Securities of Subsidiaries (Tables)

6 Months Ended

Jun. 30, 2019

Condensed Financial Information Disclosure [Abstract]

Condensed Consolidating Balance Sheet

The Company has provided the following condensed consolidating financial information in accordance with Regulation S-X Rule 3-10, Financial Statements of Guarantors and Issuers of Guaranteed Securities Registered or Being Registered.

Condensed Consolidating Balance Sheets as of June 30, 2019

(Millions)

Assets	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Cash and cash equivalents	$	0.2	$	6.2	$	60.8	$	—		$	67.2
Receivables	—		—		118.0		—			118.0
Receivables - affiliate	—		—		6.9		(6.9		)	—
Costs recoverable from customers	—		—		10.1		—			10.1
Prepayments	0.3		—		22.5		—			22.8
Advances to affiliates	3.1		7.7		2.7		(10.4		)	3.1
Other current assets	—		0.1		12.5		(1.8		)	10.8
Total current assets	3.6		14.0		233.5		(19.1		)	232.0
Investment in consolidated subsidiaries	2,977.5		7,158.0		—		(10,135.5		)	—
Property, plant and equipment, gross	0.6		—		11,481.0		—			11,481.6
Less–accumulated depreciation    and amortization	0.6		—		3,094.9		—			3,095.5
Property, plant and equipment, net	—		—		8,386.1		—			8,386.1
Advances to affiliates – noncurrent	2,020.2		727.1		95.2		(2,842.5		)	—
Other noncurrent assets	—		4.8		477.9		0.3			483.0
Total other assets	2,020.2		731.9		573.1		(2,842.2		)	483.0
Total Assets	$	5,001.3	$	7,903.9	$	9,192.7	$	(12,996.8	)	$	9,101.1

Liabilities and Partners' Capital	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Payables	$	0.3	$	0.1	$	59.1	$	—		$	59.5
Payable to affiliates	0.5		—		6.9		(6.9		)	0.5
Advances from affiliates	3.1		2.7		7.7		(10.4		)	3.1
Other current liabilities	—		28.8		147.1		(1.5		)	174.4
Total current liabilities	3.9		31.6		220.8		(18.8		)	237.5
Long-term debt and finance lease     obligation	—		2,777.0		841.8		—			3,618.8
Advances from affiliates - noncurrent	—		2,115.4		727.1		(2,842.5		)	—
Other noncurrent liabilities	—		2.4		245.0		—			247.4
Total other liabilities and deferred     credits	—		2,117.8		972.1		(2,842.5		)	247.4
Total partners' capital	4,997.4		2,977.5		7,158.0		(10,135.5		)	4,997.4
Total Liabilities and Partners' Capital	$	5,001.3	$	7,903.9	$	9,192.7	$	(12,996.8	)	$	9,101.1

Condensed Consolidating Balance Sheets as of December 31, 2018

(Millions)

Assets	Parent  Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Cash and cash equivalents	$	0.3	$	1.6	$	1.7	$	—		$	3.6
Receivables	—		—		153.7		—			153.7
Receivables - affiliate	—		—		9.5		(9.5		)	—
Costs recoverable from customers	—		—		23.6		—			23.6
Prepayments	0.3		—		21.0		—			21.3
Advances to affiliates	—		—		2.0		(2.0		)	—
Other current assets	—		—		14.3		(4.2		)	10.1
Total current assets	0.6		1.6		225.8		(15.7		)	212.3
Investment in consolidated subsidiaries	2,828.1		7,136.6		—		(9,964.7		)	—
Property, plant and equipment, gross	0.6		—		11,325.0		—			11,325.6
Less–accumulated depreciation    and amortization	0.6		—		2,939.2		—			2,939.8
Property, plant and equipment, net	—		—		8,385.8		—			8,385.8
Advances to affiliates – noncurrent	2,034.2		460.1		431.8		(2,926.1		)	—
Other noncurrent assets	0.2		2.5		446.5		1.4			450.6
Total other assets	2,034.4		462.6		878.3		(2,924.7		)	450.6
Total Assets	$	4,863.1	$	7,600.8	$	9,489.9	$	(12,905.1	)	$	9,048.7

Liabilities and Partners' Capital	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Payables	$	0.6	$	0.1	$	70.4	$	—		$	71.1
Payable to affiliates	0.5		—		9.5		(9.5		)	0.5
Advances from affiliates	—		2.0		—		(2.0		)	—
Other current liabilities	0.1		24.3		164.2		(2.8		)	185.8
Total current liabilities	1.2		26.4		244.1		(14.3		)	257.4
Long-term debt and finance lease     obligation	—		2,280.1		1,421.2		—			3,701.3
Advances from affiliates - noncurrent	—		2,466.0		460.1		(2,926.1		)	—
Other noncurrent liabilities	—		0.2		227.9		—			228.1
Total other liabilities and deferred     credits	—		2,466.2		688.0		(2,926.1		)	228.1
Total partners' capital	4,861.9		2,828.1		7,136.6		(9,964.7		)	4,861.9
Total Liabilities and Partners' Capital	$	4,863.1	$	7,600.8	$	9,489.9	$	(12,905.1	)	$	9,048.7

Condensed Consolidating Statements of Income

Condensed Consolidating Statements of Income for the Three Months Ended June 30, 2019

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Operating Revenues:
Transportation	$	—		$	—		$	314.1	$	(20.8	)	$	293.3
Storage, parking and lending	—			—			23.0		(0.1		)	22.9
Other	—			—			11.1		—			11.1
Total operating revenues	—			—			348.2		(20.9		)	327.3
Operating Costs and Expenses:
Fuel and transportation	—			—			25.1		(20.9		)	4.2
Operation and maintenance	—			—			50.7		—			50.7
Administrative and general	(0.1		)	—			37.1		—			37.0
Other operating costs and expenses	0.1			—			112.9		—			113.0
Total operating costs and expenses	—			—			225.8		(20.9		)	204.9
Operating income	—			—			122.4		—			122.4
Other Deductions (Income):
Interest expense	—			33.2			12.3		—			45.5
Interest (income) expense - affiliates, net	(18.3		)	15.2			3.1		—			—
Equity in earnings of subsidiaries	(57.4		)	(105.8		)	—		163.2			—
Miscellaneous other expense, net	—			—			1.1		—			1.1
Total other (income) deductions	(75.7		)	(57.4		)	16.5		163.2			46.6
Income (loss) before income taxes	75.7			57.4			105.9		(163.2		)	75.8
Income taxes	—			—			0.1		—			0.1
Net income (loss)	$	75.7		$	57.4		$	105.8	$	(163.2	)	$	75.7

Condensed Consolidating Statements of Income for the Three Months Ended June 30, 2018

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Operating Revenues:
Transportation	$	—		$	—		$	268.9		$	(20.4	)	$	248.5
Storage, parking and lending	—			—			21.6			—			21.6
Other	—			—			15.2			—			15.2
Total operating revenues	—			—			305.7			(20.4		)	285.3
Operating Costs and Expenses:
Fuel and transportation	—			—			24.5			(20.4		)	4.1
Operation and maintenance	—			—			50.9			—			50.9
Administrative and general	(0.1		)	—			35.8			—			35.7
Other operating costs and expenses	0.2			—			108.7			—			108.9
Total operating costs and expenses	0.1			—			219.9			(20.4		)	199.6
Operating (loss) income	(0.1		)	—			85.8			—			85.7
Other Deductions (Income):
Interest expense	—			30.7			12.6			—			43.3
Interest (income) expense - affiliates, net	(17.5		)	13.3			4.2			—			—
Interest income	—			—			(0.1		)	—			(0.1		)
Equity in earnings of subsidiaries	(24.8		)	(68.8		)	—			93.6			—
Miscellaneous other expense, net	—			—			0.2			—			0.2
Total other (income) deductions	(42.3		)	(24.8		)	16.9			93.6			43.4
Income (loss) before income taxes	42.2			24.8			68.9			(93.6		)	42.3
Income taxes	—			—			0.1			—			0.1
Net income (loss)	$	42.2		$	24.8		$	68.8		$	(93.6	)	$	42.2

Condensed Consolidating Statements of Income for the Six Months Ended June 30, 2019

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Operating Revenues:
Transportation	$	—		$	—		$	640.7		$	(41.0	)	$	599.7
Storage, parking and lending	—			—			46.9			(0.6		)	46.3
Other	—			—			27.2			—			27.2
Total operating revenues	—			—			714.8			(41.6		)	673.2
Operating Costs and Expenses:
Fuel and transportation	—			—			48.4			(41.6		)	6.8
Operation and maintenance	—			—			93.7			—			93.7
Administrative and general	(0.1		)	—			70.3			—			70.2
Other operating costs and expenses	0.2			—			226.8			—			227.0
Total operating costs and expenses	0.1			—			439.2			(41.6		)	397.7
Operating (loss) income	(0.1		)	—			275.6			—			275.5
Other Deductions (Income):
Interest expense	—			62.7			28.1			—			90.8
Interest (income) expense - affiliates, net	(37.3		)	34.3			3.0			—			—
Interest income	—			—			(0.3		)	—			(0.3		)
Equity in earnings of subsidiaries	(146.6		)	(243.6		)	—			390.2			—
Miscellaneous other expense, net	—			—			0.9			—			0.9
Total other (income) deductions	(183.9		)	(146.6		)	31.7			390.2			91.4
Income (loss) before income taxes	183.8			146.6			243.9			(390.2		)	184.1
Income taxes	—			—			0.3			—			0.3
Net income (loss)	$	183.8		$	146.6		$	243.6		$	(390.2	)	$	183.8

Condensed Consolidating Statements of Income for the Six Months Ended June 30, 2018

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Operating Revenues:
Transportation	$	—		$	—		$	588.2		$	(41.2	)	$	547.0
Storage, parking and lending	—			—			47.0			(0.3		)	46.7
Other	—			—			27.0			—			27.0
Total operating revenues	—			—			662.2			(41.5		)	620.7
Operating Costs and Expenses:
Fuel and transportation	—			—			50.0			(41.5		)	8.5
Operation and maintenance	—			—			97.3			—			97.3
Administrative and general	(0.1		)	—			67.9			—			67.8
Other operating costs and expenses	0.2			—			220.5			—			220.7
Total operating costs and expenses	0.1			—			435.7			(41.5		)	394.3
Operating (loss) income	(0.1		)	—			226.5			—			226.4
Other Deductions (Income):
Interest expense	—			62.6			24.8			—			87.4
Interest (income) expense - affiliates, net	(31.8		)	24.1			7.7			—			—
Interest income	—			—			(0.1		)	—			(0.1		)
Equity in earnings of subsidiaries	(107.7		)	(194.4		)	—			302.1			—
Miscellaneous other income, net	—			—			(0.6		)	—			(0.6		)
Total other (income) deductions	(139.5		)	(107.7		)	31.8			302.1			86.7
Income (loss) before income taxes	139.4			107.7			194.7			(302.1		)	139.7
Income taxes	—			—			0.3			—			0.3
Net income (loss)	$	139.4		$	107.7		$	194.4		$	(302.1	)	$	139.4

Condensed Consolidating Statements Of Comprehensive Income

Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended June 30, 2019

(Millions)

	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net income (loss)	$	75.7	$	57.4	$	105.8	$	(163.2	)	$	75.7
Other comprehensive income (loss):
Reclassification adjustment transferred     to Net income from cash flow hedges	0.1		0.1		0.1		(0.2		)	0.1
Pension and other postretirement     benefit costs, net of tax	1.9		1.9		1.9		(3.8		)	1.9
Total Comprehensive Income (Loss)	$	77.7	$	59.4	$	107.8	$	(167.2	)	$	77.7

Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended June 30, 2018

(Millions)

	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net income (loss)	$	42.2	$	24.8	$	68.8	$	(93.6	)	$	42.2
Other comprehensive income (loss):
Reclassification adjustment transferred     to Net income from cash flow hedges	0.2		0.2		0.2		(0.4		)	0.2
Pension and other postretirement     benefit costs, net of tax	1.2		1.2		1.2		(2.4		)	1.2
Total Comprehensive Income (Loss)	$	43.6	$	26.2	$	70.2	$	(96.4	)	$	43.6

Condensed Consolidating Statements of Comprehensive Income for the Six Months Ended June 30, 2019

(Millions)

	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net income (loss)	$	183.8	$	146.6	$	243.6	$	(390.2	)	$	183.8
Other comprehensive income (loss):
Reclassification adjustment transferred     to Net income from cash flow hedges	0.4		0.4		0.4		(0.8		)	0.4
Pension and other postretirement     benefit costs, net of tax	2.4		2.4		2.4		(4.8		)	2.4
Total Comprehensive Income (Loss)	$	186.6	$	149.4	$	246.4	$	(395.8	)	$	186.6

Condensed Consolidating Statements of Comprehensive Income for the Six Months Ended June 30, 2018

(Millions)

	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net income (loss)	$	139.4	$	107.7	$	194.4	$	(302.1	)	$	139.4
Other comprehensive income (loss):
Reclassification adjustment transferred     to Net income from cash flow hedges	0.8		0.8		0.4		(1.2		)	0.8
Pension and other postretirement     benefit costs, net of tax	1.5		1.5		1.5		(3.0		)	1.5
Total Comprehensive Income (Loss)	$	141.7	$	110.0	$	196.3	$	(306.3	)	$	141.7

Condensed Consolidating Statements of Cash Flows

Condensed Consolidating Statements of Cash Flow for the Six Months Ended June 30, 2019

(Millions)

	Parent Guarantor			Subsidiary  Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net cash provided by (used in) operating activities	$	37.0		$	(91.0	)	$	431.3		$	—		$	377.3
INVESTING ACTIVITIES:
Capital expenditures	—			—			(179.7		)	—			(179.7		)
Proceeds from sale of operating assets	—			—			2.2			—			2.2
Advances to affiliates, net	10.9			(274.7		)	110.9			149.8			(3.1		)
Net cash provided by (used in) investing activities	10.9			(274.7		)	(66.6		)	149.8			(180.6		)
FINANCING ACTIVITIES:
Proceeds from long-term debt, net of     issuance cost	—			495.2			—			—			495.2
Proceeds from borrowings on revolving     credit agreement	—			—			165.0			—			165.0
Repayment of borrowings on revolving     credit agreement	—			—			(745.0		)	—			(745.0		)
Principal payment of finance lease     obligation	—			—			(0.3		)	—			(0.3		)
Advances from affiliates, net	3.1			(124.9		)	274.7			(149.8		)	3.1
Distributions paid	(51.1		)	—			—			—			(51.1		)
Net cash (used in) provided by financing activities	(48.0		)	370.3			(305.6		)	(149.8		)	(133.1		)
(Decrease) increase in cash and cash equivalents	(0.1		)	4.6			59.1			—			63.6
Cash and cash equivalents at   beginning of period	0.3			1.6			1.7			—			3.6
Cash and cash equivalents at     end of period	$	0.2		$	6.2		$	60.8		$	—		$	67.2

Condensed Consolidating Statements of Cash Flow for the Six Months Ended June 30, 2018

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net cash provided by (used in) operating activities	$	31.4		$	(85.1	)	$	359.2		$	—		$	305.5
INVESTING ACTIVITIES:
Capital expenditures	—			—			(228.9		)	—			(228.9		)
Proceeds from sale of operating assets	—			—			0.6			—			0.6
Advances to affiliates, net	19.3			62.1			(223.8		)	142.4			—
Net cash provided by (used in) investing activities	19.3			62.1			(452.1		)	142.4			(228.3		)
FINANCING ACTIVITIES:
Repayment of borrowings from long-term     debt	—			(185.0		)	—			—			(185.0		)
Proceeds from borrowings on revolving     credit agreement	—			—			365.0			—			365.0
Repayment of borrowings on revolving     credit agreement	—			—			(215.0		)	—			(215.0		)
Principal payment of finance lease     obligation	—			—			(0.3		)	—			(0.3		)
Advances from affiliates, net	0.1			204.5			(62.1		)	(142.4		)	0.1
Distributions paid	(51.1		)	—			—			—			(51.1		)
Net cash (used in) provided by financing activities	(51.0		)	19.5			87.6			(142.4		)	(86.3		)
Decrease in cash and cash equivalents	(0.3		)	(3.5		)	(5.3		)	—			(9.1		)
Cash and cash equivalents at     beginning of period	0.3			4.6			12.7			—			17.6
Cash and cash equivalents at     end of period	$	—		$	1.1		$	7.4		$	—		$	8.5