Reportable Segments Segment Assets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	[1]	Dec. 31, 2018
Segment Reporting Information [Line Items]
Assets	$ 98,913	$ 102,805		$ 88,609
Intrastate transportation and storage
Segment Reporting Information [Line Items]
Assets	6,851	6,648
Interstate transportation and storage
Segment Reporting Information [Line Items]
Assets	17,263	18,111
Midstream
Segment Reporting Information [Line Items]
Assets	18,969	20,332
NGL and refined products transportation and services
Segment Reporting Information [Line Items]
Assets	17,082	19,145
Crude oil transportation and services
Segment Reporting Information [Line Items]
Assets	24,832	22,933
Investment In Sunoco LP [Member]
Segment Reporting Information [Line Items]
Assets	4,895	5,438
Investment In USAC [Member]
Segment Reporting Information [Line Items]
Assets	3,103	3,730
All other
Segment Reporting Information [Line Items]
Assets	$ 5,918	$ 6,468

[1] *As adjusted. See Note 1.