COMMITMENTS AND CONTINGENCIES- Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Commitments and Contingencies Disclosure [Line Items]
Operating expenses, net of insurance recoveries related to environmental expenditures	$ 14.0	$ 8.5	$ 10.6
Environmental liabilities	58.4	30.8
Guaranty amount made by El Paso which guaranteed EPME's obligations to BDL	40.0
Total rental expense	30.1	21.3	21.2
Capacity leases, remaining terms	19 years
Right of way
Commitments and Contingencies Disclosure [Line Items]
Annual rights-of-way payments	$ 6.6
Minimum
Commitments and Contingencies Disclosure [Line Items]
Capacity leases, remaining terms	1 year
Maximum
Commitments and Contingencies Disclosure [Line Items]
Capacity leases, remaining terms	15 years