Reportable Segments Capital expenditures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Capital expenditures	$ 2,270	$ 2,904	$ 3,188
Operating Segments | Natural Gas Pipelines
Segment Reporting Information [Line Items]
Capital expenditures	1,377	1,565	1,349
Operating Segments | Products Pipelines
Segment Reporting Information [Line Items]
Capital expenditures	175	199	149
Operating Segments | Terminals
Segment Reporting Information [Line Items]
Capital expenditures	347	386	893
Operating Segments | CO2
Segment Reporting Information [Line Items]
Capital expenditures	349	397	436
Operating Segments | Kinder Morgan Canada
Segment Reporting Information [Line Items]
Capital expenditures	0	332	338
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Capital expenditures	$ 22	$ 25	$ 23