Related Party Transactions - Additional Information (Details)		1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 03, 2014 USD ($)	Nov. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 USD ($) credit_facility	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Related Party Transaction [Line Items]
Indemnification liability deductible amount	$ 500,000
Aggregate liability of SPLC	15,000,000.0			$ 10,700,000.0
Statute of limitations expirations, number of days				60 days
Number of days within combined tax filing submission				90 days
Other contributions from parent				$ 3,000,000	$ 13,300,000
Gain (loss) from sale of excess allowance oil		$ (400,000)		900,000	100,000
Total amount paid back to SPLC				0	11,900,000	$ (5,100,000)
Pension and Retirement Savings Plans
Related Party Transaction [Line Items]
Pension and postretirement health and life insurance				2,900,000	3,000,000	3,200,000
Defined benefit plan costs				1,100,000	1,300,000	1,300,000
PSP
Related Party Transaction [Line Items]
Share-based compensation expense					100,000	200,000
PSP | Maximum
Related Party Transaction [Line Items]
Share-based compensation expense				$ 100,000
Shell Treasury Center West Inc
Related Party Transaction [Line Items]
Number of revolving credit facilities | credit_facility				2
Shell Treasury Center West Inc | Five Year Revolver
Related Party Transaction [Line Items]
Debt instrument term				5 years
Shell Treasury Center West Inc | 364 Day Revolver
Related Party Transaction [Line Items]
Debt instrument term				364 days
SPLC
Related Party Transaction [Line Items]
Total amount paid back to SPLC					11,900,000
General and administrative - related parties				$ 6,100,000	5,800,000	9,900,000
General insurance expense				4,000,000	3,600,000	$ 5,200,000
SPLC | Reimbursement for Maintenance Expense and Capital Expenditures
Related Party Transaction [Line Items]
Other contributions from parent				1,600,000
Zydeco Mars Bengal Poseidon Explorer and Colonial
Related Party Transaction [Line Items]
Total distributions to general partners			$ 33,300,000	253,600,000	174,500,000
Shell Pipeline Company L P
Related Party Transaction [Line Items]
Payment of general and administrative fee	$ 8,500,000
Zydeco
Related Party Transaction [Line Items]
Total distributions to general partners			$ 19,000,000	$ 119,600,000	88,900,000
Total amount paid back to SPLC					$ 6,800,000