Operations And Basis of Presentation Schedule of Impact of Accounting Changes (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019		Dec. 31, 2019		Dec. 31, 2018
Net income (loss)	$ (907)	$ 1,219	[1]	$ 5,112		$ 3,829
Inventories	1,024			1,532	[1]	1,372
Property, Plant and Equipment, Net	72,971			72,491	[1]
Current maturities of long-term debt	16			12	[1]
Cost of products sold	8,291	9,477	[1]	39,677		41,603
Operating expenses	848	808	[1]
Other non-current liabilities	1,161			1,134	[1]
Operating Lease, Liability, Noncurrent	821			895	[1]
Long-term debt, less current maturities	49,909			50,560	[1]
Operating Lease, Liability, Current	54			57	[1]
Accrued and other current liabilities	3,888			3,245	[1]
Partners' Capital	27,515			27,382	[1]	28,885
Inventory, LIFO Reserve, Period Charge	227	(93)	[1]
Net change in operating assets and liabilities, net of effects of acquisitions	113	(337)	[1]	(405)		62
Operating Income (Loss)	61	1,866	[1]	7,211		5,457
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(854)	1,345		5,312		4,099
Income (Loss) Attributable to Parent, before Tax	(854)	1,345	[1]
Net Income (Loss) Attributable to Parent	(719)	950	[1]
Comprehensive income	(926)	1,227	[1]	5,136		3,786
Comprehensive income attributable to partners	(738)	958	[1]	4,034		3,037
Assets, Current	5,056			7,344	[1]	6,515
Other Assets, Noncurrent	1,493			1,547	[1]	1,478
Assets	$ 98,913			102,805	[1]	88,609
Previously Reported [Member]
Net income (loss)		1,281		5,186		3,774
Inventories				1,935	[2]	1,677
Cost of products sold		9,415		39,603		41,658
Partners' Capital				27,289	[2]	28,718
Net change in operating assets and liabilities, net of effects of acquisitions		399		479		(117)
Operating Income (Loss)		1,928		7,285		5,402
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		1,407		5,386		4,044
Comprehensive income		1,289		5,210		3,731
Comprehensive income attributable to partners		1,020		4,108		2,982
Assets, Current				7,747	[2]	6,820
Other Assets, Noncurrent				1,051		1,006
Assets				102,712	[2]	88,442
Change in Inventory Accounting Policy [Member]
Net income (loss)		(62)		(74)		55
Inventories				(403)		(305)
Cost of products sold		62		74		(55)
Partners' Capital				93		167
Net change in operating assets and liabilities, net of effects of acquisitions		(62)		(74)		55
Operating Income (Loss)		(62)		(74)		55
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		(62)		(74)		55
Comprehensive income		(62)		(74)		55
Comprehensive income attributable to partners		$ (62)		(74)		55
Assets, Current				(403)		(305)
Other Assets, Noncurrent				496		472
Assets				$ 93		$ 167

[1] *As adjusted. See Note 1.

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