INVESTMENTS IN UNCONSOLIDATED AFFILIATES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended				3 Months Ended	1 Months Ended	3 Months Ended		6 Months Ended			3 Months Ended			6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013		Jun. 30, 2014	Jun. 30, 2013		Dec. 31, 2013	Mar. 31, 2014 Great Lakes Gas Transmission Limited Partnership	Apr. 30, 2006 Northern Border	Jun. 30, 2014 Northern Border	Jun. 30, 2013 Northern Border	Jun. 30, 2014 Northern Border	Jun. 30, 2013 Northern Border	Dec. 31, 2013 Northern Border	Jun. 30, 2014 Great Lakes	Mar. 31, 2014 Great Lakes	Jun. 30, 2013 Great Lakes	Jun. 30, 2014 Great Lakes	Jun. 30, 2013 Great Lakes		Dec. 31, 2013 Great Lakes
Investments in unconsolidated affiliates
Ownership interest at the end of the period (as a percent)										50.00%		50.00%			46.45%			46.45%
Equity Earnings from Unconsolidated Affiliates	$ 18	$ 15	[1]	$ 51	$ 33	[1]				$ 16	$ 15	$ 39	$ 31		$ 2			$ 12	$ 2
Investments in Unconsolidated Affiliates	1,184			1,184			1,195			515		515		523	669			669			672
Amortization period of transaction fee									12 years
Transaction fee									10
Additional ownership interest acquired (as a percent)									20.00%
Undistributed earnings												0	0					0	0
Equity contribution																4		4	4	[1]
Total cash call issued to fund debt repayment								9
Assets
Cash and cash equivalents										41		41		27
Current assets															56			56			52
Other current assets										34		34		34
Plant, property and equipment, net										1,182		1,182		1,197	757			757			771
Other assets										32		32		33
Assets, total										1,289		1,289		1,291	813			813			823
Liabilities and Partners' Equity
Current liabilities										63		63		51	33			33			28
Deferred credits and other										21		21		19
Long-term debt, including current maturities										411		411		411	326			326			335
Partners' equity
Partners' equity										796		796		812	454			454			460
Accumulated other comprehensive loss										(2)		(2)		(2)
Liabilities and Equity, total										1,289		1,289		1,291	813			813			823
Revenues (expenses)
Transmission revenues										69	69	155	141		29		29	77	64
Operating expenses										(16)	(19)	(34)	(38)		(12)		(15)	(24)	(30)
Depreciation										(15)	(14)	(30)	(29)		(7)		(8)	(14)	(16)
Financial charges and other										(6)	(6)	(12)	(11)		(6)		(7)	(13)	(14)
Net income/(loss)										$ 32	$ 30	$ 79	$ 63		$ 4		$ (1)	$ 26	$ 4

[1] (a) Recast as discussed in Note 2.