Commitments and Contingencies, Liquidity Option Agreement (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Liquidity Option Agreement [Abstract]
Change in fair value of Liquidity Option Agreement	$ 24.5	$ 25.4	$ 0.0
Percentage of capital stock we agreed to purchase under liquidity option agreement	100.00%
Liquidity Option exercise period	90 days
Percentage of fair market value of Enterprise units to be paid as consideration	100.00%
Trigger Event exercise period	135 days
Number of units held by limited partner (in units)	54,807,352
Level 3 [Member]
Liquidity Option Agreement [Abstract]
Liquidity option agreement	$ 269.6	$ 245.1
Level 3 [Member] | Liquidity Option Agreement [Member]
Liquidity Option Agreement [Abstract]
Fair value inputs, Assumed long-term debt	$ 2,200.0
Fair value inputs, Interest rate on assumed debt of OTA following option exercise	4.63%
Fair value inputs, Life of debt assumed after Liquidity option is exercised	30 years
Increase in fair value of liquidity option agreement if debt excluded from valuation model	$ 215.8
Fair value inputs, federal and state tax rate	38.00%
Decrease in fair value of liquidity option agreement assuming a 5% lower tax rate	$ (35.5)
Cash flow projections discount rate	7.60%
Fair value inputs, weighted-average expected ownership percentage of contributed units at beginning of option period	84.00%
Increase in fair value of liquidity option agreement assuming retention of all units	$ 50.9
Level 3 [Member] | Liquidity Option Agreement [Member] | Minimum [Member]
Liquidity Option Agreement [Abstract]
Fair value inputs, Expected life of OTA following option exercise	1 year
Fair value inputs, Estimated growth rates in Enterprise earnings before interest, taxes, depreciation and amortization	2.20%
Fair value inputs, OTA ownership interest in Enterprise common units	1.90%
Level 3 [Member] | Liquidity Option Agreement [Member] | Maximum [Member]
Liquidity Option Agreement [Abstract]
Fair value inputs, Expected life of OTA following option exercise	30 years
Fair value inputs, Estimated growth rates in Enterprise earnings before interest, taxes, depreciation and amortization	14.70%
Fair value inputs, OTA ownership interest in Enterprise common units	2.60%