CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 161.8	$ 3.1
Receivables:
Trade, net	99.9	117.2
Other	12.0	12.3
Gas transportation receivables	7.7	5.6
Gas and liquids stored underground	13.2	10.7
Prepayments	20.5	16.9
Other current assets	1.5	4.0
Total current assets	316.6	169.8
Property, Plant and Equipment:
Natural gas transmission and other plant	9,741.0	9,504.7
Construction work in progress	272.7	201.9
Property, plant and equipment, gross	10,013.7	9,706.6
Less—accumulated depreciation and amortization	2,204.4	2,052.2
Property, plant and equipment, net	7,809.3	7,654.4
Other Assets:
Goodwill	237.4	237.4
Gas stored underground	93.1	97.6
Other	138.7	141.1
Total other assets	469.2	476.1
Total Assets	8,595.1	8,300.3
Payables:
Trade	105.6	99.1
Affiliates	1.3	1.3
Other	21.0	19.5
Gas payables	5.1	4.7
Accrued taxes, other	50.8	47.3
Accrued interest	43.6	39.7
Accrued payroll and employee benefits	28.5	33.2
Deferred income	8.9	6.9
Customer rate refunds	0.0	16.3
Other current liabilities	44.3	46.4
Total current liabilities	309.1	314.4
Long-term debt and capital lease obligation	3,625.5	3,459.3
Other Liabilities and Deferred Credits:
Pension liability	24.6	24.3
Asset retirement obligation	44.7	38.1
Provision for other asset retirement	59.9	57.2
Payable to affiliate	16.0	16.0
Other	70.1	64.3
Total other liabilities and deferred credits	215.3	199.9
Commitments and Contingencies
Partners’ Capital:
Common units - 250.3 million units issued and outstanding as of June 30, 2016, and December 31, 2015	4,439.5	4,326.2
General partner	87.1	84.8
Accumulated other comprehensive loss	(81.4)	(84.3)
Total partners’ capital	4,445.2	4,326.7
Total Liabilities and Partners' Capital	$ 8,595.1	$ 8,300.3