Equity Method Investments - Schedule of Equity Investments in Affiliates Balance Affected (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016		Sep. 30, 2017		Sep. 30, 2016
Schedule of Equity Method Investments [Line Items]
Distributions Received	$ 42.5	$ 24.7		$ 125.3		$ 82.5
Income from equity investments	41.2	21.4	[1]	117.1	[2]	70.2	[1]
Purchase price adjustment	0.0			0.4	[3]	0.0	[4]
Bengal
Schedule of Equity Method Investments [Line Items]
Distributions Received	5.5	2.7		14.8		16.1
Income from equity investments	6.2	5.2		16.9		15.9
Purchase price adjustment	0.0			0.0
Odyssey
Schedule of Equity Method Investments [Line Items]
Distributions Received	4.4			13.1
Income from equity investments	5.0			13.7
Purchase price adjustment	0.0			0.0
Mars
Schedule of Equity Method Investments [Line Items]
Distributions Received	21.9	11.5		64.2		34.5
Income from equity investments	22.0	8.6		63.7		31.7
Purchase price adjustment	0.0			0.0
Poseidon
Schedule of Equity Method Investments [Line Items]
Distributions Received	9.6	10.5		28.9		31.9
Income from equity investments	7.3	$ 7.6		20.5		$ 22.6
Purchase price adjustment	0.0			0.0
Proteus
Schedule of Equity Method Investments [Line Items]
Distributions Received	0.6			2.3
Income from equity investments	0.3			1.1
Purchase price adjustment	0.0			0.3
Endymion
Schedule of Equity Method Investments [Line Items]
Distributions Received	0.5			2.0
Income from equity investments	0.4			1.2
Purchase price adjustment	$ 0.0			$ 0.1

[1] Prior period financial information has been retrospectively adjusted for the acquisition of the Shell Delta, Na Kika and Refinery Gas Pipeline Operations.

[2] The financial information for the nine months ended September 30, 2017 reflects adjustments for the acquisition of the Shell Delta, Na Kika and Refinery Gas Pipeline Operations from January 1, 2017 through May 9, 2017.

[3] The financial information for the nine months ended September 30, 2017 reflects adjustments for the acquisition of the Shell Delta,Na Kika and Refinery Gas Pipeline Operations from January 1, 2017 through May 9, 2017.

[4] Prior period financial information has been retrospectively adjusted for the acquisition of the Shell Delta, Na Kika and Refinery Gas Pipeline Operations.