Net Income Per Limited Partner Unit (Tables)

6 Months Ended

Jun. 30, 2020

Partners' Capital Notes [Abstract]

Schedule of Distributions Declared, Partners Interest in Partnership Net Income and Net Income per Unit by Class

Net income earned by the Partnership is allocated between the classes of participating securities in accordance with our partnership agreement, after giving effect to priority income allocations to the holders of the preferred units. First, earnings are allocated based on actual cash distributions declared to our unitholders. To the extent net income exceeds or is less than cash distributions declared, this difference is allocated based on the unitholders’ respective ownership percentages, after consideration of any priority allocations of earnings. For the diluted net income per limited partner unit calculation, the preferred units are assumed to be converted at the beginning of the period into common limited partner units on a one-for-one basis, and the distribution formula for available cash in our partnership agreement is recalculated, using the original available cash amount increased only for the preferred distributions which would not have been paid after conversion. 

	Millions of Dollars
	Three Months Ended June 30			Six Months Ended June 30
	2020		2019	2020	2019
Net income	$	255	233	481	431
Less:
General partners’ distributions declared (including IDRs)*	—		70	—	139
Limited partners’ distributions declared on preferred units*	9		9	19	19
Limited partners’ distributions declared on common units*	200		107	399	212
Distributions less than net income	$	46	47	63	61

*Distributions declared are attributable to the indicated periods.

	Limited Partners’ Common Units		Limited Partners’ Preferred Units	Total
Three Months Ended June 30, 2020
Net income (millions):
Distributions declared	$	200	9	209
Distributions less than net income	46		—	46
Net income (basic)	246		9	255
Dilutive effect of preferred units	9
Net income (diluted)	$	255
Weighted-average units outstanding—basic	228,340,146
Dilutive effect of preferred units	13,819,791
Weighted-average units outstanding—diluted	242,159,937
Net income per limited partner unit—basic (dollars)	$	1.07
Net income per limited partner unit—diluted (dollars)	1.05

	Limited Partners’ Common Units		General Partner (including IDRs)	Limited Partners’ Preferred Units	Total
Three Months Ended June 30, 2019
Net income (millions):
Distributions declared	$	107	70	9	186
Distributions less than net income	46		1	—	47
Net income (basic)	153		71	9	233
Dilutive effect of preferred units*	6
Net income (diluted)	$	159
Weighted-average units outstanding—basic	124,824,010
Dilutive effect of preferred units*	13,819,791
Weighted-average units outstanding—diluted	138,643,801
Net income per limited partner unit—basic (dollars)	$	1.23
Net income per limited partner unit—diluted (dollars)	1.15
*The dilutive effect of preferred units assumes the reallocation of net income to the limited and general partners, including a reallocation associated with IDRs, pursuant to the available cash formula in the partnership agreement.

	Limited Partners’ Common Units		Limited Partners’ Preferred Units	Total
Six Months Ended June 30, 2020
Net income (millions):
Distributions declared	$	399	19	418
Distributions less than net income	63		—	63
Net income (basic)	462		19	481
Dilutive effect of preferred units	19
Net income (diluted)	$	481
Weighted-average units outstanding—basic	228,326,203
Dilutive effect of preferred units	13,819,791
Weighted-average units outstanding—diluted	242,145,994
Net income per limited partner unit—basic (dollars)	$	2.02
Net income per limited partner unit—diluted (dollars)	1.99

	Limited Partners’ Common Units		General Partner (including IDRs)	Limited Partners’ Preferred Units	Total
Six Months Ended June 30, 2019
Net income (millions):
Distributions declared	$	212	139	19	370
Distributions less than net income	60		1	—	61
Net income (basic)	272		140	19	431
Dilutive effect of preferred units*	14
Net income (diluted)	$	286
Weighted-average units outstanding—basic	124,542,536
Dilutive effect of preferred units*	13,819,791
Weighted-average units outstanding—diluted	138,362,327
Net income per limited partner unit—basic (dollars)	$	2.19
Net income per limited partner unit—diluted (dollars)	2.07
*The dilutive effect of preferred units assumes the reallocation of net income to the limited and general partners, including a reallocation associated with IDRs, pursuant to the available cash formula in the partnership agreement.