Earnings Per Unit (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
BASIC EARNINGS PER COMMON UNIT
Net income attributable to common unitholders		$ 1,340.4	$ 1,350.1
Earnings allocated to phantom unit awards	[1]	(11.0)	(9.9)
Net income allocated to common unitholders		$ 1,329.4	$ 1,340.2
Basic weighted-average number of common units outstanding (in units)		2,183.4	2,188.9
Basic earnings per common unit (in dollars per unit)		$ 0.61	$ 0.61
DILUTED EARNINGS PER COMMON UNIT
Net income attributable to common unitholders		$ 1,340.4	$ 1,350.1
Net income attributable to preferred units		0.9	0.0
Net income attributable to limited partners		$ 1,341.3	$ 1,350.1
Diluted weighted-average number of units outstanding:
Distribution-bearing common units (in units)		2,183.4	2,188.9
Phantom units (in units)	[2]	17.4	15.1
Preferred units (in units)	[2]	2.5	0.0
Total (in units)		2,203.3	2,204.0
Diluted earnings per common unit (in dollars per unit)		$ 0.61	$ 0.61

[1] Phantom units are considered participating securities for purposes of computing basic earnings per unit. See Note 12 for information regarding our phantom units.

[2] We use the “if-converted method” to determine the potential dilutive effect of the vesting of phantom unit awards and the conversion of preferred units outstanding.  See Note 12 for information regarding phantom unit awards.  See Note 8 for information regarding preferred units.