Reportable Segments Reportable Segments Assets (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 71,784	$ 74,157
Corporate and intersegment eliminations
Segment Reporting Information [Line Items]
Assets	2,670	1,966
Natural Gas Pipelines
Segment Reporting Information [Line Items]
Assets	48,375	50,310
Products Pipelines
Segment Reporting Information [Line Items]
Assets	9,258	9,468
Terminals
Segment Reporting Information [Line Items]
Assets	8,786	8,890
CO2
Segment Reporting Information [Line Items]
Assets	$ 2,695	$ 3,523