Reportable Segments Operating expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Operating expenses(c)	$ 6,280	$ 7,288	$ 7,215
Operating Segments | Natural Gas Pipelines
Segment Reporting Information [Line Items]
Operating expenses(c)	4,213	5,218	5,371
Operating Segments | Products Pipelines
Segment Reporting Information [Line Items]
Operating expenses(c)	684	748	564
Operating Segments | Terminals
Segment Reporting Information [Line Items]
Operating expenses(c)	888	823	793
Operating Segments | CO2
Segment Reporting Information [Line Items]
Operating expenses(c)	496	453	394
Operating Segments | Kinder Morgan Canada
Segment Reporting Information [Line Items]
Operating expenses(c)	0	72	95
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating expenses(c)	$ (1)	$ (26)	$ (2)