UNAUDITED CONDENSED STATEMENTS OF CONSOLIDATED EQUITY - USD ($) $ in Millions	Total	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]	Limited Partners [Member]
Balance at Dec. 31, 2017	$ 22,772.4	$ (171.7)	$ 225.2	$ 22,718.9
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	911.5	0.0	10.8	900.7
Cash distributions paid to limited partners	(918.5)	0.0	0.0	(918.5)
Cash payments made in connection with distribution equivalent rights	(3.9)	0.0	0.0	(3.9)
Cash distributions paid to noncontrolling interests	(15.4)	0.0	(15.4)	0.0
Cash contributions from noncontrolling interests	0.1	0.0	0.1	0.0
Net cash proceeds from the issuance of common units	177.0	0.0	0.0	177.0
Common units issued in connection with employee compensation	39.1	0.0	0.0	39.1
Amortization of fair value of equity-based awards	26.0	0.0	0.0	26.0
Cash flow hedges	10.5	10.5	0.0	0.0
Other	(33.9)	0.0	(9.1)	(24.8)
Balance at Mar. 31, 2018	22,964.9	(161.2)	211.6	22,914.5
Balance at Dec. 31, 2018	24,292.2	50.9	438.7	23,802.6
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	1,280.4	0.0	19.9	1,260.5
Cash distributions paid to limited partners	(950.4)	0.0	0.0	(950.4)
Cash payments made in connection with distribution equivalent rights	(4.5)	0.0	0.0	(4.5)
Cash distributions paid to noncontrolling interests	(18.0)	0.0	(18.0)	0.0
Cash contributions from noncontrolling interests	34.8	0.0	34.8	0.0
Net cash proceeds from the issuance of common units	42.7	0.0	0.0	42.7
Common units issued in connection with employee compensation	45.6	0.0	0.0	45.6
Amortization of fair value of equity-based awards	32.0	0.0	0.0	32.0
Repurchase of common units under 2019 Buyback Program	(51.6)	0.0	0.0	(51.6)
Cash flow hedges	(144.3)	(144.3)	0.0	0.0
Other	(37.6)	(0.6)	(12.0)	(25.0)
Balance at Mar. 31, 2019	$ 24,521.3	$ (94.0)	$ 463.4	$ 24,151.9