Equity and Distributions, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			$ 50.9	$ (171.7)
Other comprehensive income (loss) for period, before reclassifications			(19.5)	3.9
Reclassification of losses (gains) to net income during period			(42.1)	44.6
Total other comprehensive income (loss) for period	$ 83.3	$ 38.0	(61.6)	48.5
Accumulated Other Comprehensive Income (Loss), Ending balance	(10.7)	(123.2)	(10.7)	(123.2)
Interest expense	290.1	274.6	567.3	526.7
Revenue	(8,276.3)	(8,467.5)	(16,819.8)	(17,766.0)
Operating costs and expenses	6,800.9	7,552.0	13,820.6	15,774.7
Total	(1,236.5)	(687.2)	(2,516.9)	(1,598.7)
Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			(104.8)	(165.1)
Other comprehensive income (loss) for period, before reclassifications			(5.2)	14.6
Reclassification of losses (gains) to net income during period			18.4	19.9
Total other comprehensive income (loss) for period			13.2	34.5
Accumulated Other Comprehensive Income (Loss), Ending balance	(91.6)	(130.6)	(91.6)	(130.6)
Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			152.7	(10.1)
Other comprehensive income (loss) for period, before reclassifications			(13.7)	(10.2)
Reclassification of losses (gains) to net income during period			(60.5)	24.7
Total other comprehensive income (loss) for period			(74.2)	14.5
Accumulated Other Comprehensive Income (Loss), Ending balance	78.5	4.4	78.5	4.4
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Accumulated Other Comprehensive Income (Loss), Beginning Balance			3.0	3.5
Other comprehensive income (loss) for period, before reclassifications			(0.6)	(0.5)
Reclassification of losses (gains) to net income during period			0.0	0.0
Total other comprehensive income (loss) for period			(0.6)	(0.5)
Accumulated Other Comprehensive Income (Loss), Ending balance	2.4	3.0	2.4	3.0
Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Total	7.0	48.6	(42.1)	44.6
Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member] | Cash Flow Hedges [Member] | Interest Rate Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Interest expense	9.2	9.4	18.4	19.9
Reclassification out of Accumulated Other Comprehensive Income (Loss) [Member] | Cash Flow Hedges [Member] | Commodity Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Abstract]
Revenue	(2.5)	39.4	(67.8)	25.4
Operating costs and expenses	$ 0.3	$ (0.2)	$ 7.3	$ (0.7)