Reportable Segments Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 74,157.0	$ 78,866.0
Goodwill	21,451.0	21,965.0	$ 22,162.0
Natural Gas Pipelines
Segment Reporting Information [Line Items]
Assets	50,310.0	50,261.0
Products Pipelines
Segment Reporting Information [Line Items]
Assets	9,468.0	9,598.0
Terminals
Segment Reporting Information [Line Items]
Assets	8,890.0	9,415.0
CO2
Segment Reporting Information [Line Items]
Assets	3,523.0	3,928.0
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Assets	$ 1,966.0	5,664.0
Previously Reported [Member] | Natural Gas Pipelines
Segment Reporting Information [Line Items]
Assets		51,562.0
Previously Reported [Member] | Products Pipelines
Segment Reporting Information [Line Items]
Assets		8,429.0
Previously Reported [Member] | Terminals
Segment Reporting Information [Line Items]
Assets		9,283.0
Restatement Adjustment [Member] | Natural Gas Pipelines
Segment Reporting Information [Line Items]
Goodwill		(450.0)
Restatement Adjustment [Member] | Products Pipelines
Segment Reporting Information [Line Items]
Goodwill		$ 450.0