Retrospective Adjustment - Statement of Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenue
Third parties	$ 51.3	$ 46.5	[1]
Related parties	25.4	19.4	[1]
Total revenue	76.7	65.9	[1]
Costs and expenses
Operations and maintenance – third parties	9.4	9.4	[1]
Operations and maintenance – related parties	5.4	5.2	[1]
General and administrative – third parties	2.1	1.7	[1]
General and administrative – related parties	5.7	5.6	[1]
Depreciation, amortization and accretion	5.9	5.2	[1],[2]
Property and other taxes	3.2	3.4	[1]
Total costs and expenses	31.7	30.5	[1]
Operating income	45.0	35.4	[1]
Income from equity investments	23.2	12.5	[1]
Dividend income from investment	2.8	1.6	[1]
Investment and dividend income	26.0	14.1	[1]
Interest expense, net	3.0	0.2	[1]
Income before income taxes	68.0	49.3	[1]
Income tax expense	0.0	0.2	[1]
Net income	68.0	49.1	[1],[2]
Less: Net income attributable to Parent	0.0	7.7	[1]
Net income attributable to the Partnership	$ 55.3	23.6	[1]
Pecten
Revenue
Third parties		46.5
Related parties		19.4
Total revenue		65.9
Costs and expenses
Operations and maintenance – third parties		9.4
Operations and maintenance – related parties		5.2
General and administrative – third parties		1.7
General and administrative – related parties		5.6
Depreciation, amortization and accretion		5.2
Property and other taxes		3.4
Total costs and expenses		30.5
Operating income		35.4
Income from equity investments		12.5
Dividend income from investment		1.6
Investment and dividend income		14.1
Interest expense, net		0.2
Income before income taxes		49.3
Income tax expense		0.2
Net income		49.1
Less: Net income attributable to Parent		7.7
Less: Net income attributable to noncontrolling interests		17.8
Net income attributable to the Partnership		23.6
Shell Midstream Partners, L.P. | Pecten
Revenue
Third parties		41.3
Related parties		10.4
Total revenue		51.7
Costs and expenses
Operations and maintenance – third parties		6.9
Operations and maintenance – related parties		3.9
General and administrative – third parties		1.6
General and administrative – related parties		5.0
Depreciation, amortization and accretion		3.4
Property and other taxes		3.2
Total costs and expenses		24.0
Operating income		27.7
Income from equity investments		12.5
Dividend income from investment		1.6
Investment and dividend income		14.1
Interest expense, net		0.2
Income before income taxes		41.6
Income tax expense		0.2
Net income		41.4
Less: Net income attributable to Parent		0.0
Less: Net income attributable to noncontrolling interests		17.8
Net income attributable to the Partnership		23.6
Shell Auger and Lockport Operations | Pecten
Revenue
Third parties		5.2
Related parties		9.0
Total revenue		14.2
Costs and expenses
Operations and maintenance – third parties		2.5
Operations and maintenance – related parties		1.3
General and administrative – third parties		0.1
General and administrative – related parties		0.6
Depreciation, amortization and accretion		1.8
Property and other taxes		0.2
Total costs and expenses		6.5
Operating income		7.7
Income from equity investments		0.0
Dividend income from investment		0.0
Investment and dividend income		0.0
Interest expense, net		0.0
Income before income taxes		7.7
Income tax expense		0.0
Net income		7.7
Less: Net income attributable to Parent		7.7
Less: Net income attributable to noncontrolling interests		0.0
Net income attributable to the Partnership		$ 0.0

[1] (1) The 2015 financial information has been retrospectively adjusted for the acquisition of the Shell Auger and Lockport Operations.

[2] (1) The 2015 financial information has been retrospectively adjusted for the acquisition of the Shell Auger and Lockport Operations.