CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current Assets:
Cash and cash equivalents	$ 28.8	$ 6.6
Receivables:
Trade	103.2	102.6
Other	31.9	8.3
Gas transportation receivables	6.1	9.1
Gas and liquids stored underground	5.3	4.1
Prepayments	11.5	14.5
Other current assets	5.3	4.4
Total current assets	192.1	149.6
Property, Plant and Equipment:
Natural gas transmission and other plant	9,317.1	9,250.1
Construction work in progress	95.5	105.5
Property, plant and equipment, gross	9,412.6	9,355.6
Less—accumulated depreciation and amortization	1,845.5	1,766.4
Property, plant and equipment, net	7,567.1	7,589.2
Other Assets:
Goodwill	237.4	237.4
Gas stored underground	88.6	86.4
Other	142.9	144.2
Total other assets	468.9	468.0
Total Assets	8,228.1	8,206.8
Payables:
Trade, net	49.2	51.7
Affiliates	0.8	1.5
Other	25.7	10.4
Gas payables	9.6	8.5
Accrued taxes, other	31.8	47.1
Accrued interest	39.4	47.4
Accrued payroll and employee benefits	13.7	26.3
Deferred income	3.9	1.9
Other current liabilities	26.7	25.4
Total current liabilities	200.8	220.2
Long-term debt and capital lease obligation	3,568.1	3,689.7
Other Liabilities and Deferred Credits:
Pension liability	19.1	19.2
Asset retirement obligation	39.9	39.9
Provision for other asset retirement	61.0	60.5
Payable to affiliate	16.0	16.0
Other	60.1	59.0
Total other liabilities and deferred credits	196.1	194.6
Commitments and Contingencies
Partners’ Capital:
Common units – 249.9 million units and 243.3 million units issued and outstanding as of March 31, 2015, and December 31, 2014	4,254.2	4,095.1
General partner	83.2	80.0
Accumulated other comprehensive loss	(74.3)	(72.8)
Total partners’ capital	4,263.1	4,102.3
Total Liabilities and Partners' Capital	$ 8,228.1	$ 8,206.8