Net Income Per Limited Partner Unit (Tables)

12 Months Ended

Dec. 31, 2019

Partners' Capital Notes [Abstract]

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

	Millions of Dollars
	2019		2018	2017
Net income attributable to the Partnership	$	923	796	461
Less:
General partner’s distributions declared (including IDRs)*	139		236	158
Limited partners’ distributions declared on preferred units*	37		37	9
Limited partners’ distributions declared on common units*	609		382	291
Distributions less than net income attributable to the Partnership	$	138	141	3

*Distributions declared are attributable to the indicated periods.

	2019
	Limited Partners’ Common Units		General Partner (including IDRs)	Limited Partners’ Preferred Units	Total
Net income attributable to the Partnership (millions):
Distributions declared	$	609	139	37	785
Distributions less than net income attributable to the Partnership	137		1	—	138
Net income attributable to the Partnership (basic)	746		140	37	923
Dilutive effect of preferred units(1)	32
Net income attributable to the Partnership (diluted)	$	778
Weighted-average units outstanding—basic	167,655,306
Dilutive effect of preferred units(1)	13,819,791
Weighted-average units outstanding—diluted	181,475,097
Net income attributable to the Partnership per limited partner unit—basic (dollars)	$	4.45
Net income attributable to the Partnership per limited partner unit—diluted (dollars)	4.29

⁽¹⁾ The dilutive effect of the 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.

	2018
	Limited Partners’ Common Units		General Partner (including IDRs)	Limited Partners’ Preferred Units	Total
Net income attributable to the Partnership (millions):
Distributions declared	$	382	236	37	655
Distributions less than net income attributable to the Partnership	137		4	—	141
Net income attributable to the Partnership (basic)	519		240	37	796
Dilutive effect of preferred units(1)	28
Net income attributable to the Partnership (diluted)	$	547
Weighted-average units outstanding—basic	122,768,582
Dilutive effect of preferred units(1)	13,819,791
Weighted-average units outstanding—diluted	136,588,373
Net income attributable to the Partnership per limited partner unit—basic (dollars)	$	4.22
Net income attributable to the Partnership per limited partner unit—diluted (dollars)	4.00

⁽¹⁾ The dilutive effect of the 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.

	2017
	Limited Partners’ Common Units		General Partner (including IDRs)	Limited Partners’ Preferred Units	Total
Net income attributable to the Partnership (millions):
Distributions declared	$	291	158	9	458
Distributions less than net income attributable to the Partnership	1		2	—	3
Net income attributable to the Partnership (basic)	292		160	9	461
Dilutive effect of preferred units(1)	7
Net income attributable to the Partnership (diluted)	$	299
Weighted-average units outstanding—basic	112,044,824
Dilutive effect of preferred units(1)	3,294,032
Weighted-average units outstanding—diluted	115,338,856
Net income attributable to the Partnership per limited partner unit—basic (dollars)	$	2.60
Net income attributable to the Partnership per limited partner unit—diluted (dollars)	2.59

⁽¹⁾ The dilutive effect of the 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.