Operations And Basis of Presentation Schedule of Impact of Accounting Changes (Details) - USD ($) $ in Millions	3 Months Ended					9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019		Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019		Dec. 31, 2019		Dec. 31, 2018
Net income (loss)	$ (362)	$ 5,112	$ 1,250	[1]	$ 3,829	$ (557)	$ 3,751	[1]
Inventories	1,723					1,723			$ 1,532	[1]	$ 1,372
Property, Plant and Equipment, Net	74,838					74,838			73,896	[1]
Current maturities of long-term debt	21					21			26	[1]
Cost of products sold	6,376	39,677	9,864	[1]	41,603	18,784	29,642	[1]
Operating expenses	773		806	[1]		2,422	2,406	[1]
Other non-current liabilities	1,152					1,152			1,162	[1]
Operating Lease, Liability, Noncurrent	901					901			901	[1]
Long-term debt, less current maturities	51,352					51,352			50,904	[1]
Operating lease current liabilities	54					54			60	[1]
Accrued and other current liabilities	2,905					2,905			3,336	[1]
Partners' Capital	25,478					25,478			27,382	[1]	28,885
Inventory, LIFO Reserve, Period Charge						126	(71)	[1]
Net change in operating assets and liabilities, net of effects of acquisitions		(405)	(103)		62	103	(290)	[1]
Operating Income (Loss)	248	7,211	1,860	[1]	5,457	1,655	5,554	[1]
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(320)	5,312	1,305	[1]	4,099	(388)	3,967	[1]
Income (Loss) Attributable to Parent, before Tax	(320)		1,305	[1]		(388)	3,967	[1]
Net Income (Loss) Attributable to Parent	(657)		977	[1]		(896)	2,930	[1]
Comprehensive income	(336)	5,136	1,243	[1]	3,786	(503)	3,753	[1]
Comprehensive income attributable to partners	(631)	4,034	970	[1]	3,037	(842)	2,932	[1]
Assets, Current	6,163					6,163			7,485	[1]	6,515
Other Assets, Noncurrent	1,582					1,582			1,571	[1]	1,478
Assets	97,522					$ 97,522			102,294	[1]	88,609
Previously Reported [Member]
Net income (loss)		5,186	1,224		3,774		3,786
Inventories									1,935	[2]	1,677
Cost of products sold		39,603	9,890		41,658		29,607
Partners' Capital									27,289	[2]	28,718
Net change in operating assets and liabilities, net of effects of acquisitions		479	77		(117)		325
Operating Income (Loss)		7,285	1,834		5,402		5,589
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		5,386	1,279		4,044		4,002
Comprehensive income		5,210	1,217		3,731		3,788
Comprehensive income attributable to partners		4,108	944		2,982		2,967
Assets, Current									7,888	[2]	6,820
Other Assets, Noncurrent									1,075	[2]	1,006
Assets									102,201	[2]	88,442
Revision of Prior Period, Change in Accounting Principle, Adjustment [Member]
Net income (loss)	$ 265
Inventories									(403)		(305)
Partners' Capital									93
Assets, Current									(403)
Other Assets, Noncurrent									496
Assets									$ 93
Change in Inventory Accounting Policy [Member]
Net income (loss)		(74)	26		55		(35)
Cost of products sold		74	(26)		(55)		35
Partners' Capital											167
Net change in operating assets and liabilities, net of effects of acquisitions		(74)	26		55		(35)
Operating Income (Loss)		(74)	26		55		(35)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		(74)	26		55		(35)
Comprehensive income		(74)	26		55		(35)
Comprehensive income attributable to partners		$ (74)	$ 26		$ 55		$ (35)
Assets, Current											(305)
Other Assets, Noncurrent											472
Assets											$ 167

[1] *As adjusted. See Note 1.

[2] * Amounts reflect the retrospective consolidation of the SemGroup entities discussed above.