Equity and Distributions, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Abstract]
Beginning balance			$ (171.7)	$ (280.0)
Other comprehensive income (loss) before reclassifications			3.9	170.6
Amounts reclassified from accumulated other comprehensive loss (income)			44.6	(19.3)
Total other comprehensive income (loss)	$ 38.0	$ (12.5)	48.5	151.3
Ending balance	(123.2)	(128.7)	(123.2)	(128.7)
Interest expense	274.6	245.8	526.7	495.1
Revenue	(8,467.5)	(6,607.6)	(17,766.0)	(13,928.0)
Operating costs and expenses	7,552.0	5,730.2	15,774.7	12,063.4
Total	(687.2)	(666.0)	(1,598.7)	(1,437.0)
Gains (Losses) on Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Beginning balance			(165.1)	(199.8)
Other comprehensive income (loss) before reclassifications			14.6	(4.5)
Amounts reclassified from accumulated other comprehensive loss (income)			19.9	19.6
Total other comprehensive income (loss)			34.5	15.1
Ending balance	(130.6)	(184.7)	(130.6)	(184.7)
Gains (Losses) on Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Beginning balance			(10.1)	(83.8)
Other comprehensive income (loss) before reclassifications			(10.2)	175.2
Amounts reclassified from accumulated other comprehensive loss (income)			24.7	(38.9)
Total other comprehensive income (loss)			14.5	136.3
Ending balance	4.4	52.5	4.4	52.5
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Beginning balance			3.5	3.6
Other comprehensive income (loss) before reclassifications			(0.5)	(0.1)
Amounts reclassified from accumulated other comprehensive loss (income)			0.0	0.0
Total other comprehensive income (loss)			(0.5)	(0.1)
Ending balance	3.0	3.5	3.0	3.5
Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Total	48.6	(36.0)	44.6	(19.3)
Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member] | Gains (Losses) on Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Interest expense	9.4	10.0	19.9	19.6
Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member] | Gains (Losses) on Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Revenue	39.4	(46.0)	25.4	(38.5)
Operating costs and expenses	$ (0.2)	$ 0.0	$ (0.7)	$ (0.4)