Supplemental Financial Statement Information Schedule Of Statements of Cash Flows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
NET CASH FLOWS PROVIDED BY OPERATING ACTIVITIES	$ 575	$ 829
Cash paid for Bakken Pipeline Transaction	(370)	(214)
Contributions to unconsolidated affiliates	34	50
Capital expenditures	2,158	942
Net cash used in investing activities	(2,585)	(801)
Proceeds from borrowings	8,731	3,170
Repayments of long-term debt	(5,938)	(1,977)
Distributions to partners	244	195
Units repurchased under buyback program	0	366
Debt issuance costs	(33)	(17)
Net cash provided by (used in) financing activities	3,026	392
INCREASE IN CASH AND CASH EQUIVALENTS	1,016	420
CASH AND CASH EQUIVALENTS, beginning of period	847	590
CASH AND CASH EQUIVALENTS, end of period	1,863	1,010
Parent Company [Member]
NET CASH FLOWS PROVIDED BY OPERATING ACTIVITIES	198	229
Cash paid for Bakken Pipeline Transaction	(817)	0
Contributions to unconsolidated affiliates	0	7
Capital expenditures	(5)	0
Cash received from affiliate	54	0
Net cash used in investing activities	(768)	(7)
Proceeds from borrowings	1,692	405
Repayments of long-term debt	(865)	(56)
Distributions to partners	(244)	(195)
Units repurchased under buyback program	0	(366)
Debt issuance costs	(11)	(2)
Net cash provided by (used in) financing activities	572	(214)
INCREASE IN CASH AND CASH EQUIVALENTS	2	8
CASH AND CASH EQUIVALENTS, beginning of period	2	8
CASH AND CASH EQUIVALENTS, end of period	$ 4	$ 16