Earnings Per Unit (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
BASIC EARNINGS PER COMMON UNIT
Net income attributable to common unitholders		$ 3,774.7	$ 4,591.3	$ 4,172.4
Earnings allocated to phantom unit awards	[1]	(32.0)	(27.7)	(21.5)
Net income allocated to common unitholders		$ 3,742.7	$ 4,563.6	$ 4,150.9
Basic weighted-average number of common units outstanding (in units)		2,185.8	2,188.6	2,176.5
Basic earnings per common unit (in dollars per unit)		$ 1.71	$ 2.09	$ 1.91
DILUTED EARNINGS PER COMMON UNIT
Net income attributable to common unitholders		$ 3,774.7	$ 4,591.3	$ 4,172.4
Net income attributable to preferred units		0.9	0.0	0.0
Net income attributable to limited partners		$ 3,775.6	$ 4,591.3	$ 4,172.4
Diluted weighted-average number of units outstanding:
Distribution-bearing common units (in units)		2,185.8	2,188.6	2,176.5
Phantom units (in units)	[2]	15.7	13.1	10.5
Preferred units (in units)	[2]	0.7	0.0	0.0
Total (in units)		2,202.2	2,201.7	2,187.0
Diluted earnings per common unit (in dollars per unit)		$ 1.71	$ 2.09	$ 1.91

[1] Phantom units are considered participating securities for purposes of computing basic earnings per unit. See Note 13 for information regarding our phantom units. 

[2] We use the “if-converted method” to determine the potential dilutive effect of the vesting of phantom units and the conversion of preferred units outstanding.  See Note 8 for information regarding the preferred units issued during 2020.