Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended																	3 Months Ended	12 Months Ended			12 Months Ended		12 Months Ended			12 Months Ended		12 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Constitution Pipeline Company Llc [Member]	Dec. 31, 2013 Bluegrass Pipeline Company Llc [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member] Cash and Cash Equivalents [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Property Plant And Equipment [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member] Property Plant And Equipment [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Accounts Payable [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member] Accounts Payable [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Accrued Liabilities [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member] Accrued Liabilities [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Other Current Liabilities [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member] Other Current Liabilities [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Other Noncurrent Liabilities [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member] Other Noncurrent Liabilities [Member]	Jun. 30, 2013 Variable Interest Entity, Primary Beneficiary [Member] Gulfstar One [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Gulfstar One [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Gulfstar One [Member] Estimated Remaining Construction Costs For Variable Interest Entity [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Gunflint [Member] Estimated Remaining Construction Costs For Variable Interest Entity [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Constitution Pipeline Company Llc [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Constitution Pipeline Company Llc [Member] Estimated Remaining Construction Costs For Variable Interest Entity [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Bluegrass Pipeline Company Llc [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Bluegrass Pipeline Company Llc [Member] Estimated Remaining For Spending Under Preliminary Activities Budget [Member]	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary [Member] Bluegrass Pipeline Company Llc [Member] Property Plant And Equipment [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary [Member] Laurel Mountain [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary [Member] Laurel Mountain [Member] Equity Method Investments [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary [Member] Caiman Energy II LLC [Member]	Jan. 31, 2014 Variable Interest Entity, Not Primary Beneficiary [Member] Caiman Energy II LLC [Member] Subsequent Event [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary [Member] Caiman Energy II LLC [Member] Equity Method Investments [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary [Member] Moss Lake [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary [Member] Moss Lake [Member] Estimated Remaining For Spending Under Preliminary Activities Budget [Member]	Dec. 31, 2013 Variable Interest Entity, Not Primary Beneficiary [Member] Moss Lake [Member] Equity Method Investments [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage				41.00%	50.00%														51.00%			41.00%		50.00%			51.00%		47.50%			50.00%
Other commitment																				$ 325	$ 134		$ 600		$ 85								$ 25
Contributions from noncontrolling interests	467	13	0															187
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																		49.00%
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets						122	8	1,111	556																	113
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities										(145)	(128)	(3)	0	(10)	0	(115)	(109)
Variable Interest Entity, Nonconsolidated, Comparison of Carrying Amount of Assets and Liabilities to Maximum Loss Exposure [Abstract]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net																												481			256			12
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount																											$ 481		$ 380	$ 500