This item represents disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation; these investments are accounted for under the equity method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Total distributions to each class of partners (i.e., general, limited and preferred partners).

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RELATED PARTY TRANSACTIONS - Distribution from Affiliate (Details) - USD ($) $ in Millions			6 Months Ended
	Jul. 18, 2016	Jun. 16, 2016	Jun. 30, 2016	Jan. 01, 2016
Related party transactions
Partnership distribution			$ 131
Portland Natural Gas Transmission System
Related party transactions
Ownership interest (as a percent)	49.90%		49.90%	49.90%
Distribution declared \| Portland Natural Gas Transmission System
Related party transactions
Partnership distribution		$ 8
Cash Distribution Paid \| Portland Natural Gas Transmission System
Related party transactions
Partnership's share of distributions declared and payable by investee	$ 4