Note 11 - Equity and Net Earnings per Unit Equity, Net Earnings per Unit (Details) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended																9 Months Ended	12 Months Ended
		Dec. 31, 2018 USD ($) $ / shares		Sep. 30, 2018 USD ($) $ / shares		Jun. 30, 2018 USD ($) $ / shares		Mar. 31, 2018 USD ($) $ / shares		Dec. 31, 2017 USD ($) $ / shares		Sep. 30, 2017 USD ($) $ / shares		Jun. 30, 2017 USD ($) $ / shares		Mar. 31, 2017 USD ($) $ / shares		Sep. 30, 2017 $ / shares	Dec. 31, 2018 USD ($) $ / shares shares		Dec. 31, 2017 USD ($) $ / shares shares		Dec. 31, 2016 USD ($) $ / shares shares
Net earnings		$ 171		$ 166	[1]	$ 132	[1]	$ 131	[1]	$ 53	[1]	$ 90	[1]	$ 90	[1]	$ 73	[1]		$ 600	[2],[3],[4]	$ 306	[2],[3],[4]	$ 277	[2],[3],[4],[5]
Special Allocation Of Net Earnings																			0		(1)	[6]	(3)	[6]
Net Earnings, Excluding Noncontrolling Interest and Including Special Allocations																			600		307		280
Distributions on Preferred Units (c)	[7]																		(41)		(3)		0
Net earnings attributable to common units	[2]																		559		304		280
General Partner Distributions																			0		(81)		(158)
General partner's IDRs																					(50)
Limited Partner's Distributions on units																			(890)		(611)		(344)
Distributions greater than earnings																			$ (331)		$ (388)		$ (222)
Common units - basic (units) | shares																			228.7		126.0		98.2
Common units - diluted (units) | shares	[8]																		228.9		126.1		98.2
Common - basic (dollars per unit) | $ / shares		$ 0.66	[9]	$ 0.68	[9]	$ 0.63	[9]	$ 0.59	[9]	$ 0.25	[9]	$ 0.90	[9]	$ 0.63	[9]	$ 0.51	[9]		$ 2.57	[10]	$ 2.11	[10]	$ 1.87	[10]
Common - diluted (dollars per unit) | $ / shares		$ 0.66	[9]	$ 0.68	[9]	$ 0.63	[9]	$ 0.59	[9]	$ 0.25	[9]	$ 0.90	[9]	$ 0.63	[9]	$ 0.51	[9]		$ 2.57	[10]	$ 2.11	[10]	$ 1.87	[10]
Incentive Distribution, Distribution Split Marginal Percentage																		50.00%
Incentive Distribution, Minimum Distribution Level | $ / shares																		0.3881
Distribution to Partner, Waived Distribution																			$ 60		$ 25
Loss attributable to Predecessors																			(28)		(43)		$ (62)
General Partner
General Partner Distributions																			0		(6)		(10)
Distributions greater than earnings	[11]																		28		44		65
Total partner's earnings (loss) on units																			(28)		37		93
Loss attributable to Predecessors																			0		0		0
Common
Special Allocation Of Net Earnings																			0		(1)	[6]	(3)	[6]
Limited Partner's Distributions on units	[12]																		(890)		(611)		(344)
Distributions greater than earnings																			(303)		(344)		(157)
Total partner's earnings (loss) on units																			587		266		184
Loss attributable to Predecessors																			$ 0		$ 0		$ 0

[1] Adjusted to include the historical results of the Predecessors. See Notes 1 and 2 for further discussion.

[2] Adjusted to include the historical results of the Predecessors. See Notes 1 and 2 for further discussion.

[3] Adjusted to include the historical results of the Predecessors. See Notes 1 and 2 for further discussion.

[4] All periods include the historical results of the Predecessors. See Notes 1 and 2 for further discussion.

[5] All periods include the historical results of the Predecessors. See Notes 1 and 2 for further discussion.

[6] Normal allocations according to percentage interests are made after giving effect, if any, to priority income allocations in an amount equal to incentive cash distributions fully allocated to the general partner and any special allocations. The adjustment reflects the special allocation to common units held by TLGP for the interest incurred in connection with borrowings on the Dropdown Credit Facility in lieu of using cash on hand to fund the North Dakota Gathering and Processing Assets in 2017 and the Alaska Storage and Terminalling Assets acquisition in 2016.

[7] The Preferred Units entitle unitholders to receive preferred distributions on a semi-annually basis.

[8] Diluted net earnings per unit include the effects of potentially dilutive units on our common units, which consist of unvested service and performance phantom units.

[9] The sum of four quarters may not equal annual results due to rounding or the quarterly number of units outstanding.

[10] Amounts may not recalculate due to rounding of dollar and unit information.

[11] We have revised the historical allocation of general partner earnings to include the Predecessors’ losses of $28 million, $43 million and $62 million for the years ended December 31, 2018, 2017 and 2016, respectively.

[12] Distributions of earnings for limited partners’ common units for the years ended December 31, 2018 and 2017 is net of a $60 million and $25 million waiver, respectively, from our Sponsor in connection with the WNRL Merger.