Reportable Segments Reportable Segments Assets (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 73,530	$ 74,157
Corporate and intersegment eliminations
Segment Reporting Information [Line Items]
Assets	3,061	1,966
Natural Gas Pipelines
Segment Reporting Information [Line Items]
Assets	49,393	50,310
Products Pipelines
Segment Reporting Information [Line Items]
Assets	9,310	9,468
Terminals
Segment Reporting Information [Line Items]
Assets	8,840	8,890
CO2
Segment Reporting Information [Line Items]
Assets	$ 2,926	$ 3,523