Note 11 - Equity and Net Earnings per Unit Equity, Equity Transactions related to Acquisitions (Details) - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Stock [Line Items]
Allocation of net assets acquired by the unitholders			$ 0	$ 0	$ 0
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	[1]		0.00%	0.00%	2.00%
Payments to Acquire Businesses, Gross		$ 300	$ 300	$ 406	$ 760	[2]
Increase (Decrease) In Equity Balance Due To Acquisitions			(1,400)	(1,300)	443
Common
Class of Stock [Line Items]
Allocation of net assets acquired by the unitholders			$ 1,651	$ 1,713	$ 310

[1] In connection with the IDR/GP Transaction, our general partner units converted into non-economic general partner units.

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