Guarantee of Securities of Subsidiaries (Tables)

3 Months Ended

Mar. 31, 2019

Condensed Financial Information Disclosure [Abstract]

Condensed Consolidating Balance Sheet

The Partnership 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 March 31, 2019

(Millions)

Assets	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Cash and cash equivalents	$	0.1	$	2.4	$	12.8	$	—		$	15.3
Receivables	—		—		133.8		—			133.8
Receivables - affiliate	—		—		7.1		(7.1		)	—
Costs recoverable from customers	—		—		16.2		—			16.2
Prepayments	0.3		—		13.3		—			13.6
Advances to affiliates	—		—		2.2		(2.2		)	—
Other current assets	—		—		9.9		(2.2		)	7.7
Total current assets	0.4		2.4		195.3		(11.5		)	186.6
Investment in consolidated subsidiaries	2,918.1		7,195.2		—		(10,113.3		)	—
Property, plant and equipment, gross	0.6		—		11,389.7		—			11,390.3
Less–accumulated depreciation    and amortization	0.6		—		3,015.3		—			3,015.9
Property, plant and equipment, net	—		—		8,374.4		—			8,374.4
Advances to affiliates – noncurrent	2,027.6		490.3		434.1		(2,952.0		)	—
Other noncurrent assets	—		5.2		469.7		0.2			475.1
Total other assets	2,027.6		495.5		903.8		(2,951.8		)	475.1
Total Assets	$	4,946.1	$	7,693.1	$	9,473.5	$	(13,076.6	)	$	9,036.1

Liabilities and Partners' Capital	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Payables	$	0.4	$	0.1	$	57.6	$	—		$	58.1
Payable to affiliates	0.5		—		7.1		(7.1		)	0.5
Advances from affiliates	—		2.2		—		(2.2		)	—
Other current liabilities	—		27.4		117.2		(1.9		)	142.7
Total current liabilities	0.9		29.7		181.9		(11.2		)	201.3
Long-term debt and finance lease     obligation	—		2,280.9		1,366.5		—			3,647.4
Advances from affiliates - noncurrent	—		2,461.7		490.3		(2,952.0		)	—
Other noncurrent liabilities	—		2.7		239.6		(0.1		)	242.2
Total other liabilities and deferred     credits	—		2,464.4		729.9		(2,952.1		)	242.2
Total partners' capital	4,945.2		2,918.1		7,195.2		(10,113.3		)	4,945.2
Total Liabilities and Partners' Capital	$	4,946.1	$	7,693.1	$	9,473.5	$	(13,076.6	)	$	9,036.1

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 March 31, 2019

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Operating Revenues:
Transportation	$	—		$	—		$	326.6		$	(20.2	)	$	306.4
Storage, parking and lending	—			—			23.9			(0.5		)	23.4
Other	—			—			16.1			—			16.1
Total operating revenues	—			—			366.6			(20.7		)	345.9
Operating Costs and Expenses:
Fuel and transportation	—			—			23.3			(20.7		)	2.6
Operation and maintenance	—			—			43.0			—			43.0
Administrative and general	—			—			33.2			—			33.2
Other operating costs and expenses	0.1			—			113.9			—			114.0
Total operating costs and expenses	0.1			—			213.4			(20.7		)	192.8
Operating (loss) income	(0.1		)	—			153.2			—			153.1
Other Deductions (Income):
Interest expense	—			29.5			15.8			—			45.3
Interest (income) expense - affiliates, net	(19.0		)	19.1			(0.1		)	—			—
Interest income	—			—			(0.3		)	—			(0.3		)
Equity in earnings of subsidiaries	(89.2		)	(137.8		)	—			227.0			—
Miscellaneous other income, net	—			—			(0.2		)	—			(0.2		)
Total other (income) deductions	(108.2		)	(89.2		)	15.2			227.0			44.8
Income (loss) before income taxes	108.1			89.2			138.0			(227.0		)	108.3
Income taxes	—			—			0.2			—			0.2
Net income (loss)	$	108.1		$	89.2		$	137.8		$	(227.0	)	$	108.1

Condensed Consolidating Statements of Income for the Three Months Ended March 31, 2018

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Operating Revenues:
Transportation	$	—		$	—		$	319.3		$	(20.8	)	$	298.5
Storage, parking and lending	—			—			25.4			(0.3		)	25.1
Other	—			—			11.8			—			11.8
Total operating revenues	—			—			356.5			(21.1		)	335.4
Operating Costs and Expenses:
Fuel and transportation	—			—			25.5			(21.1		)	4.4
Operation and maintenance	—			—			46.4			—			46.4
Administrative and general	—			—			32.1			—			32.1
Other operating costs and expenses	—			—			111.8			—			111.8
Total operating costs and expenses	—			—			215.8			(21.1		)	194.7
Operating income	—			—			140.7			—			140.7
Other Deductions (Income):
Interest expense	—			31.9			12.2			—			44.1
Interest (income) expense - affiliates, net	(14.3		)	10.8			3.5			—			—
Equity in earnings of subsidiaries	(82.9		)	(125.6		)	—			208.5			—
Miscellaneous other income, net	—			—			(0.8		)	—			(0.8		)
Total other (income) deductions	(97.2		)	(82.9		)	14.9			208.5			43.3
Income (loss) before income taxes	97.2			82.9			125.8			(208.5		)	97.4
Income taxes	—			—			0.2			—			0.2
Net income (loss)	$	97.2		$	82.9		$	125.6		$	(208.5	)	$	97.2

Condensed Consolidating Statements Of Comprehensive Income

Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended March 31, 2019

(Millions)

	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net income (loss)	$	108.1	$	89.2	$	137.8	$	(227.0	)	$	108.1
Other comprehensive income (loss):
Reclassification adjustment transferred     to Net income from cash flow hedges	0.3		0.3		0.3		(0.6		)	0.3
Pension and other postretirement     benefit costs, net of tax	0.5		0.5		0.5		(1.0		)	0.5
Total Comprehensive Income (Loss)	$	108.9	$	90.0	$	138.6	$	(228.6	)	$	108.9

Condensed Consolidating Statements of Comprehensive Income for the Three Months Ended March 31, 2018

(Millions)

	Parent Guarantor		Subsidiary Issuer		Non-guarantor Subsidiaries		Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net income (loss)	$	97.2	$	82.9	$	125.6	$	(208.5	)	$	97.2
Other comprehensive income (loss):
Reclassification adjustment transferred     to Net income from cash flow hedges	0.6		0.6		0.2		(0.8		)	0.6
Pension and other postretirement     benefit costs, net of tax	0.3		0.3		0.3		(0.6		)	0.3
Total Comprehensive Income (Loss)	$	98.1	$	83.8	$	126.1	$	(209.9	)	$	98.1

Condensed Consolidating Statements of Cash Flows

Condensed Consolidating Statements of Cash Flow for the Three Months Ended March 31, 2019

(Millions)

	Parent Guarantor			Subsidiary  Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net cash provided by (used in)     operating activities	$	18.8		$	(44.9	)	$	192.5		$	—		$	166.4
INVESTING ACTIVITIES:
Capital expenditures	—			—			(74.0		)	—			(74.0		)
Proceeds from sale of operating assets	—			—			0.1			—			0.1
Advances to affiliates, net	6.6			(30.2		)	(82.5		)	106.1			—
Net cash provided by (used in)     investing activities	6.6			(30.2		)	(156.4		)	106.1			(73.9		)
FINANCING ACTIVITIES:
Proceeds from borrowings on revolving     credit agreement	—			—			125.0			—			125.0
Repayment of borrowings on revolving     credit agreement	—			—			(180.0		)	—			(180.0		)
Principal payment of finance lease     obligation	—			—			(0.2		)	—			(0.2		)
Advances from affiliates, net	—			75.9			30.2			(106.1		)	—
Distributions paid	(25.6		)	—			—			—			(25.6		)
Net cash (used in) provided by     financing activities	(25.6		)	75.9			(25.0		)	(106.1		)	(80.8		)
(Decrease) increase in cash and cash   equivalents	(0.2		)	0.8			11.1			—			11.7
Cash and cash equivalents at   beginning of period	0.3			1.6			1.7			—			3.6
Cash and cash equivalents at     end of period	$	0.1		$	2.4		$	12.8		$	—		$	15.3

Condensed Consolidating Statements of Cash Flow for the Three Months Ended March 31, 2018

(Millions)

	Parent Guarantor			Subsidiary Issuer			Non-guarantor Subsidiaries			Eliminations			Consolidated Boardwalk Pipeline Partners, LP
Net cash provided by (used in)     operating activities	$	14.1		$	(36.3	)	$	174.1		$	—		$	151.9
INVESTING ACTIVITIES:
Capital expenditures	—			—			(110.9		)	—			(110.9		)
Proceeds from sale of operating assets	—			—			0.5			—			0.5
Advances to affiliates, net	11.5			(53.7		)	(115.7		)	157.9			—
Net cash provided by (used in)     investing activities	11.5			(53.7		)	(226.1		)	157.9			(110.4		)
FINANCING ACTIVITIES:
Proceeds from borrowings on revolving     credit agreement	—			—			145.0			—			145.0
Repayment of borrowings on revolving     credit agreement	—			—			(145.0		)	—			(145.0		)
Principal payment of finance lease     obligation	—			—			(0.1		)	—			(0.1		)
Advances from affiliates, net	—			104.2			53.7			(157.9		)	—
Distributions paid	(25.6		)	—			—			—			(25.6		)
Net cash (used in) provided by     financing activities	(25.6		)	104.2			53.6			(157.9		)	(25.7		)
Increase in cash and cash     equivalents	—			14.2			1.6			—			15.8
Cash and cash equivalents at     beginning of period	0.3			4.6			12.7			—			17.6
Cash and cash equivalents at     end of period	$	0.3		$	18.8		$	14.3		$	—		$	33.4